This guide assumes that you are already familiar with Qud. You will find better guides for beginners elsewhere on Steam, as well as on the Official Caves of Qud Wiki on Gamepedia.

Feel free to skip the "Basics" sections. That's boring stuff that you probably knew anyway, it's just included for thoroughness.

Hitting the mutation level cap doesn't permanently hurt you, it just means you won't benefit from those extra levels until your experience level catches up. You can ignore this.

If you only have one physical mutation that you want to put ALL of your RA's on, adhere to the following rule: Only put a single MP into that mutation at levels 8, 16, 18, 26, 28, 36, 38, 46, and 48. Notice the pattern? It's every level ending in 6 or 8, with the exception of level 6.

Yes, it takes 48 levels before you can raise the base level of a mutation to 10 without the RA's butting up against the level cap... but if you somehow manage to get there, a level 25 mutation (10 + 5 RA's) is nothing to scoff at.

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If you split the RA's between two mutations, adhere to the following rule: For the first mutation you RA, spend one MP at levels 8, 10, 12, 14, 16, 18... and again at levels 26, 28, 30, 32. For the second mutation you RA, spend up to 4 MP to bring your total mutation level up to 5, then spend one MP at levels 16, 18, 20, 22, 24, 26.

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If you split the RA's between three mutations, you will only hit the level cap once or twice in the early game. I don't recommend this as you'd have to spend a total of 3*9=27 MP to get three mutations to level 10 in order for the RA's to boos them to 13 - that's a very heavy MP investment that could have been spent on 27/4= ~6 new mutations.

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You also have the option of not investing any MPs into a physical mutation, and just dumping RA's into it occasionally. This forfeits going over the mutation level 10 cap in exchange for being able to spend MPs on more mutations. This is a good option for Esper builds that only took the one physical mutation - just to have something spend RAs on.

Some attributes have interactions with mutations.


Strength

Burrowing Claws - like all unarmed damage, there is no strength cap. The more strength, the more damage you will do... though you would need a LOT of strength to make claws better than vibro weapons.

Horns - like all unarmed damage, there is no strength cap. Same issue as burrowing claws, but has respectable damage at low levels. TESTING NEEDED: According to an outdated wiki, the accuracy of Horns is based on the mutation level, not agility, making Horns useful for melee builds that make the questionable decision to dump agility.

Stinger - NO INTERACTION WITH STRENGTH.

Multiple Legs - The increase to carry weight is percentage based, so the higher your base strength, the more carry weight you get.


Agility

Burrowing Claws - To hit chance is based on Agility.

Horns - TESTING NEEDED: No benefit from agility?

Stinger - TESTING NEEDED: No benefit from agility?


Toughness

Regeneration - The mutation increases natural healing by a percentage, so the higher your Toughness + Willpower modifier, the greater the benefit.

Photosynthetic - The mutation increases natural healing by a percentage, so the higher your Toughness + Willpower modifier, the greater the benefit. Note that Regeneration and Photosynthetic stack.


Intelligence

Psychometry - There is nothing Psychometry can do that high intelligence can't. This mutation is best on builds that make the questionable decision of dumping intelligence, choosing the Dystechnia mental defect, or both.


Willpower

Cooldowns of all abilities - be they from skills, mutations, or items - are modified by willpower. At 16 willpower, no effect on cooldowns. At 10 willpower, cooldowns are INCREASED by 30%. At 32 willpower, cooldowns are reduced by a maximum of 80%, down to a minimum of 5 turns. That means a cooldown of 20 from Frozen Hands, or a cooldown of 100 from Cryokinesis, becomes 5 and 20 respectively at 32 willpower.

Mutations with "charges", such as Light Manipulation, Quills, and Electrical Discharge, receive a bonus or penalty to charge gain instead of to cooldown.

The one exception is Mass Mind. For balance reasons, it is impossible to reduce the cooldown with Willpower. (Before the mutation rebalance, it was possible for a midgame Willpower + Ego Esper to spam Mass Mind every 5 turns to reset the cooldown on Temporal Fugue.)


Ego

The ego modifier buffs ALL mental mutations. The only exceptions are the 1 point abilities like Kindle, Sense Psychic, and Telepathy.

You would think that Ego would be the most important stat for Esper builds, but it's actually my favorite dumpstat for Espers. Ego is by far the easiest stat to farm (though it's still tedious) and by far the easiest to find stat boosting gear for (though it's a tad dangerous).

More importantly, the higher Ego gets, the fewer mental mutations you can acquire before Glimmer becomes a problem. There's a reason Six Day Stilt vendors sell Humble Pies that permanently reduce your ego. That said, with the right build and gear, Glimmer is a blessing in disguise...

At character generation, you can choose a Morphotype. The options are Chimera, Esper, and Unstable Genome.

Chimera (D tier): You can to only take physical mutations, in exchange for a chance to gain extra limbs. This is questionable tradeoff, as it prevents choosing any of the Esper abilities. Even a physical mutant build wants Precog. That said, I'll admit that Chimeras are VERY fun to play.

Esper (F tier): You can only take mental mutations, in exchange for... nothing. No physical mutations means no RAs, which means by level 25 you lost the chance for 9 mutation levels. If you have Precog, there are ways to reset your genome until you get a mutation you are happy with - no need to pick the Esper Morphotype, even if you only plan to grab Esper mutations.

It's also worth noting that there are late game methods of gaining mental mutations without spending MPs. They are highly limited, risky, costly, and dependent on RNG, but they exist.

Unstable Genome (RNG Tier): The fun one. It costs 3 MP, and you can pick it more than once. After each level up, there is a 33% chance you get a choice of 3 mutations. If you're lucky, you spent 3 MP on Unstable Genome, which gets you Freezing Hands which would normally costs 5 MP at chargen. You could also get unlucky, and have to choose between Horns, Quills, and Photosynthetic Skin. Either way, you'll wind up with a unique build you wouldn't have or couldn't have chosen otherwise.

Note that if you have 5 copies of Unstable Genome, you are statistically unlikely to mutate 5 times before level 25ish... and, unless you get a good mutation early, you are statistically unlikely to survive past level 10. For normal players, a single copy of Unstable Genome is more than enough to add variety to your build. (I enjoy Precog + 4 copies of Unstable Genome with a -4 defect.)

TLDR, the best defect is Hooked Feet, followed closely by Brittle Bones, and Amphibious. These are not necessarily the most "fun" defects, but they are strictly speaking the best. See below for details.

In the current version of the game, Brittle Bones is by far the best defect, albeit the least flavorful.



+2 Physical Defect

Cold Blooded (B)
If you don't mind the micro of going into your inventory to drink a dram of lava diluted in a waterskin full of honey once every 5 minutes, this "penalty" gives a reliable +10 quickness.

Albino (C)
Regenerate HP slower in sunlight. If you spend time in the CAVES of Qud, this is a free point. No big benefit, no big penalty.

Electromagnetic Impulse (D)
If you don't want your get-out-of-death-free gadgets breaking at bad times, you'll need to invest in a lot of expensive tinkering to shield them from EMP. Still, this is occasionally handy if you hate robots even if it isn't reliable.

Numb (F)
You won't know if you just got hit for 1% of your health, or 24% of your health.

Carnivorous (F)
Unless you really, really hate cooking, and all the superpowers it gives you, do not become a carnivore. Many of the best ingredients, like Yondercane and Hoarshrooms, are vegetarian.


+3 Physical Defect

Amphibious (A)
Even with 10 Ego, thirst quickly becomes a non-issue. The starting quest reward lets you teleport back to your starting village at will. The starting village has a Tinker, who will happily recharge your teleportation gadget in exchange for water... and you can earn water by selling your bronze trash to him.

Spontaneous Combustion (B)
The damage from being on fire is insignificant past the early game. Combine with "X happens when you catch fire" cooking recipes for some entertaining albeit unreliable shennanigans.

Myopic (F)
Do you like being insta-killed by things outside your range of vision?


+4 Physical Defect

Brittle Bones (A)
In the early game blunt weapons are common, in the late game explosions are common. That said, in the late game it usually isn't the HP damage that kills you - it's the instant kills and status effects. There are also many ways to gain/regain HP, and even a few ways to mitigate explosive weapons.

Tonic Allergy (B)
Once you start buying Urberries in the mid game, salve tonics become obsolete. Various mid-late game gadgets render the other tonics obsolete, as well. That said, tonics are cheap and weigh nothing, while Urberries are expensive heavy.

Hooks For Feet (SSS)
If you have a means of regenerating limbs and enough HP to tank the bleeding, you can get your "bad" feet dismembered and regrown as "good" feet. That's right, this is the only defect that has ZERO consequences as long as you can survive the early game.

Hooks For Feet (F)
You lose an equipment slot, permanently.

Irritable Genome (F)
There are only two reasons to take this: You are a masochist with Precog, or a masochist who loves RNG. Luckily, your RA's aren't random.


+2 Mental Defects

Socially Repugnant (D)
Unlocks some weird dialogue. Otherwise, the measly 2 points aren't worth it even if money and reputation are easily fixed.

Amnesia (F)
Do you enjoy autoexploring areas over and over? Do you enjoy not knowing whether you are in a cave you cleared, or if death might be around the next corner?

Dystechnia (D)
If you have the patience to bring artifacts to Tinkers instead of identifying them yourself, this is no big deal... but you only get a measly 2 points.


+3 Mental Defects

Evil Twin (FFF)
Most of the exploits that let you steal your twin's stuff got patched. Now it's just a deathtrap. That said, it's an incredibly entertaining deathtrap, and a personal favorite of mine.

Blinking Tic (F)
Annoying, potentially fatal.

Narcolepsy (F)
Fatal.

Quantum Jitters (F)
If nothing else, this defect "fixes" the SDS+Proselytze exploit. For masochists only.


+4 Mental Defects

Psionic Migraines (F)
There are only two reasons to take this. 1) You have Horns, and can't wear helmets anyway. 2) This is the only 4 point defect if you take the Esper Morphotype... which means you are an Esper that can't use RAs, can't wear Two Faced Knollworm Skulls, and can't dominate the two best robots in the game with the <REDACTED>.

RA's let you level physical mutations past 10. Mutations are balanced to be worthy of endgame characters are mutation level 10. What happens to the math when you push that limit? Which mutations are worth not just levelling - but OVER levelling?

For the purposes of this guide, I am rating mutations in the following manner:

S - Scales VERY well. Each additional RA breaks the math of the game even further in your favor. The only thing more OP than an Esper is an Esper with RA's in this mutation.

A - Scales well. Worth a few RAs, but it's not game breaking.

B - Scales well up to level 10, but it's not worth using RAs to push it further.

C - Fun, but not necessarily "good".

D - Not great, but if it's your only choice, you can make it work.

F - Objectively bad.

Take everything I say with a grain of salt. I am no expert on Qud, and I am certainly no expert on how to have fun. There's a reason I usually play with Unstable Genome instead of cookie cutter min/maxed builds.

<Formulas of Mutation>
<Cooldown> (<Cooldown with 32 Willpower>)

Level 1: <Properties of mutation at Experience Level 1, Mutation Cap of 1>
Level 18: <Properties of mutation at Experience Level 18, Mutation Cap of 10>
Level 36: <Properties of mutation at Experience Level 36, Mutation Cap of 19, requires at least 3 of the 4 RA's earned by level 36.>

<My opinion>

Level 1 describes the mutation at character generation. This describes your early game survivability.
Level 18 describes a mutation at mutation level 10, the maximum if you DON'T use RAs.
Level 36 describes a mutation at mutation level 10, with at least three RAs invested in it.



S Tier mutations are objectively OP. If you have this mutation, you can put ALL your RA's into it and be happy. Heck, even if you don't put any RA's in, it's STILL a great mutation.

A Tier mutations are are amazing, even if they aren't broken like the S tier ones are.

B Tier mutations are situational. They CAN be amazing, but only for specific builds under specific circumstances using specific playstyles. Under those specific circumstances they might be better than A and S tier mutations.

C Tier is objectively lame. Not necessarily bad, but NEVER worth putting RA's in.

D Tier is objectively bad. There are some upsides to enjoy if RNG forced this mutation on you, but it's not worth investing in.

F Tier is objectively bad, with no upsides. There might still be fun to be had if RNG or RP bestows this upon you, but it's the "fun" kind of "fun" if you know what I mean.



Disclaimer:

My use of the word "objective" is highly "subjective."

If any of the frequent updates (or the wiki) provide formulas that differ from the ones I provide, it is possible that this guide is out of date.

I am here to provide an opinion to those lacking one. For more reliable information, consult the wiki or the patch notes. (Or make use of the in game Debug menu to test things out yourself!)

Cooldown: 100 (20)
Duration: 20 rounds*
Bonus Quickness of 9+Mutation**
Physical Mutation Bonus: +(Mutation/3)

Level 1: Bonus Quickness of +10.
Level 18: Bonus Quickness of +19, +3 to all physical mutations.
Level 36: Bonus Quickness of +38, +6 to all physical mutations.

Each RA gives +1 to all physical mutations while this ability is active. If you have more than 3 good physical mutations, this is a good trade. Probably not as good as overlevelling a single mutation.

Good synergy with passives, so that you don't have to juggle cooldowns. Bad synergy with any mutation that doesn't gain much from a single level - which is most of them. Like all active abilities, it's only useful if you don't forget to use it.

*Bonus moves as a result of extra quickness do not count as rounds, so you get more than 20 actions. +10 quickness means +1 bonus rounds every 10 rounds, or +10% extra rounds.

**Each RA in Adrenal Control grants half the quickness of an RA in Heightened Quickness or Photosynthetic, but if you have all three and use Adrenal Control to boost them, you get nearly twice the quickness per RA. Using Adrenal Control right before Basking lets you keep the boost all day.

Four successful attacks against a wall destroy it (even when wielding weapons).
Unarmed attack is Claws (1d2 short blade) instead of Fist (1d2-1 cudgel)
Claws do more damage at higher mutation levels.

Level 1: Claws deal 1d2 damage. (Bronze tier.)
Level 18: Claws deal 1d6 damage. (Carbide tier.)
Level 36: Claws deal 1d12 damage. (Just below Zetachrome tier.)
Level 36+: WARNING! No Benefit after Mutation Level 19! NEVER use more than 3 RAs!

You can still wear gloves "around your claws" with no penalty.
You can still hold normal weapons in your hands, to use instead of claws.
Mutually exclusive with the Freezing Ray and Flaming Ray mutations.

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With Burrowing Claws 19, you get Zetachrome tier damage... except your claws can't be Tinkered to be Masterwork Serrated Freezing... in exchange for destroying any wall in 4-8 turns.

With Burrowing Claws and Double Muscled, you get more damage from dumping RA's into Double Muscled for the extra penetrations than you do from dumping RA's into the claws themselves. Even then, you get pitiful damage against late game enemies.

If you want to dig, you can just use a Pickaxe, or an Acid Grenade, or a Resonance Grenade, or a jackhammer, or get temporary claws from a Skulk injector, or spend 500 turns hitting a wall with iron weapons.

Only get Burrowing Claws if you do a lot of digging - and to be fair, few things are as OP as turning all fights into 1v1 fights by digging a short tunnel. This is why I'm rating is a (D) instead of (F). Even then, that first mutation level is all you'll ever need - don't invest MPs or RAs into this.

AV Bonus: 3+(RoundDown(Mutation/2))
DV Penalty: -2
Double AV Bonus and DV Penalty with Tighten Carapace*
Heat Resist of 5+(5*Mutation)
Cold Resist of 5+(5*Mutation)
Cannot wear Body Armor

Level 1: AV +3, DV -2, 5 heat/cold resist. (Steel Tier.)
Level 18: AV +8, DV -2, 55 heat/cold resist. (Zetachrome Tier.)
Level 36: AV +12, DV -2, heat/cold IMMUNITY. (???? Tier.)

It should be noted that the best endgame armor is Neutron Flux + Precog. The main selling point of Carapace is the Heat/Cold Resist, NOT the armor.*

A Level 10 Carapace is equivalent to Zetachrome armor, except it cannot be Tinkered, has no electric/acid resistance, but has MUCH higher Heat/Cold resist. At EXP level 32, two RA's can reach mutation level 16, which provides 85 elemental resist. At the Weathered skill from Endurance for 100 innate heat/cold immunity - even if something happens to your armor (such as from losing limbs while standing in lava).

If you want 100 resist from armor alone, this mutation isn't technically necessary. Weathered 15 + Woolly Body Armor/cloak/gloves/boots/helmet 10+4*4 + Zetachrome body/gloves/boots/helmet 11+6*3 + <SPOILER> mask 10 = 80 heat/cold resist. With a Thermo Cask armor, some luck with artifacts, or a mutation that grants extra limbs, it's technically possible to get the remaining 20 heat/cold resist without Carapace.

Heat/Cold immunity prevents being set on fire/slowed by temperature, grants immunity to heat based attacks such as from thermal grenades, and immunity to hot liquids like lava and cold gases like cryogenic mist. You can even detonate certain grenades from your inventory with impunity.

Sadly, any RA's past the first two are pointless. Getting Heat/Cold resist over 100 doesn't make lava heal you. Anything that can get past the +12 AV on your Carapace (and the additional +12 AV from Zetachrome helmets, gloves, and boots) is probably bypassing armor entirely - such as with explosion or electric damage.

*The doubled AV from Tighten Carapace is gamebreaking against most mid game threats, to the point that it makes Regeneration viable as a mid-fight heal.

**Rumour has it that if you somehow survive descending the first 100 cave layers of Qud, every level after that is made of nothing but Lava, Magma Crabs, and the occasional Extradimensional hunter. You could say this is the "hell" of Qud - and a two RA Carapace theoretically lets you survive indefinitely there.

Immunity to Corrosive Gas (NOT immunity to Acid! Just the gas.)
Corrosive Gas damages enemies, walls, and furniture, but NOT items.
Cooldown 40 (5)
Release 100 gas to all 8 adjacent squares every round for 2+Mutation rounds*
Gas Damage (Creatures/Robots)**: ( Density × MutationLevel ) / 200
Gas Damage (Walls/Furniture)***: ( 0.75 × MutationLevel + 0.25 ) × Density

Level 1: 3 rounds of gas generation, enough kill anything early game in 1-3 rounds.
Level 18: 12 rounds of gas generation, enough to kill anything mid-late game in 2-3 rounds, no cooldown at 32 willpower, easily fill half the map with gas.
Level 36: 21 rounds of gas generation, kills everything, easily fill the entire map with gas.

I originally rated Corrosive Gas as (C) tier. That was back before I used it. It is obscene.


Note that the damage gets MULTIPLIED by the density. In this image, you can see what happens when I let my gas get super dense by sitting still for 14 rounds, then wait for the gas to drift over to the Seeker sitting just outside my gas cloud. This was at MutationLevel 12. If he hadn't died, he would be suffering 84 damage EVERY ROUND.



Note: Corrosive Gas, like all gases, messes with the AI pathfinding. If they aren't in your gas, they will waste time going around it, or not chasing you at all. If they are in thin gas, they will try to avoid going into dense gas, mindlessly taking chip damage until they die. If they are in dense gas, they will pursue you mindlessly into even denser gas, where they will suffer upwards of 40 damage per turn.

Pathfinding makes Corrosive Gas good even at Mutation Level 1 in the late game, the obscene damage scaling makes it good at MutationLevel 10 even without RA's, and the damage with RA's... is just obscene.

Sadly, there are downsides. Angering or killing friendly legendaries, baetyls, and merchants is a huge risk. Not that you need them anyway, this mutation is everything you could ever want.

*Due to bonus turns from Quickness or Move Speed, the gas might not appear until the round AFTER you activate this ability.

***By level 10, most walls melt within a turn of standing next to them.

Bonus Strength: 2 + (Mutation - 1) / 2)*
Daze Chance: 13% + Mutation * 2 for 2-3 rounds.

Level 1: +2 Strength, 15% chance to daze.
Level 18: +6 Strength, 33% chance to daze.
Level 36: +11 Strength, 51% chance to daze.

Double Muscled: Boring but a good choice. You don't take this mutation for the strength - you take it for the daze. Stats like strength can be farmed with some difficulty, but getting a chance to permastun enemies is incredibly powerful.

Dazed: -4 agility (aka -2 dodge), -10 move speed, and getting Dazed again results in a Stun.

With cudgels (daze chance stacks, and can stun in one hit if both sources of daze trigger at once), daggers (high attack speed), shields (separate source of stun, good offhand "weapon"), dual wielding (increased odds of offhand weapon hitting and triggering daze), multiple arms (similar benefit as dual wielding), and stun weapons (stun buttons), it is very easy to stun a single enemy - no matter how powerful - indefinitely.

WIP: Some enemies might resist or be immune to stuns. Wiki is unclear on this point, testing needed.

The strength bonus is also nice, but falls off late game. Unless you somehow reach experience level 85 and find weapons that aren't strength-capped, you won't have enough Strength to penetrate Chrome Pyramid armor. You are better off using Vibro weapons (ignore armor and strength), crit fishing with Masterwork Serrated weapons (partially ignores armor, strength, dodge, and agility), or resorting to elemental/explosive attacks (completely ignores armor, strength, dodge, and agility).

*Each RA gives about 1.5 strength, which increases carrying capacity by about 15 lbs. Strength also helps against forced movement saves, and obviously allows carrying more gear and loot.

Max Charge: 2,000 + Mutation * 2,000
Charge per Turn: Mutation * 100 (Mutation * 180)
Discharge Damage: 1d4 per 1,000 Charge
Maximum Targets: 1 per 1,000 Charge, reduced damage to each subsequent target.
Getting hit by EMP causes involuntary discharge.
Can drink Charge from Energy Cells.
Can supply power to Jacked items.

Level 1: 4d4 damage to up to 4 targets every 40 turns.
Level 18: 22d4 damage to up to 22 targets every 40 turns.
Level 36: 40d4 damage to up to 40 targets every 40 turns. (~20 turns at 32 Willpower)

Insanely good. The only physical mutation that competes* and WINS** against most*** aspects of Espers. Forgive me for the wall of text.

Damage: At level 1 and 16 willpower, you get a 4d4 (avg 10) electrical attack (best element vs robots, rarest elemental resistance) against up to 4 targets... at an effective cooldown of 40 turns (avg 1 damage per 4 turns). For comparison, the mighty Freezing Ray does 1d3+1 (avg 3) damage with a 20 turn cooldown (avg 3/5 of a damage per 4 turns).

Max Charge: An extra 2d4 max damage per level. An extra 6d4 max damage per RA.

Charge Per Turn: At level 1 and 16 willpower, you gain 100 charge per turn. A Solar Cell only gets 10 charge per turn. The legendary Radio Powered Antimatter Cell? 80 power per turn, and only if you are no deeper than 9 layers into the caves. Each mutation level gives +100 charge per turn. Each RA, +300 charges per turn.

CAUTION: Very prone to angering friendlies, especially if EMPs are causing involuntary discharges.

NOTE: Items can receive a maximum of three Tinkering modifications. If you choose to Jack your laser rifle, you only have two more modifications to choose from. Jacked requires Tinkering II, as well as the required crafting materials and recipes. Endgame gadgets have great utility, but underwhelming DPS.

NOTE: Some items, such as the Arc Cannon, can be powered without the need for the Jacked mod.

*Deals more burst damage than any Mental Mutation, with the exception of Temporal Fugue and the 10th turn of Sunder Mind.

**By mutation level 10, with a decent willpower, you can keep a Jacked Forcefield Bracelet AND a Jacked Hologram Bracelet on indefinitely, and still have leftover charge.

***Can't compete with Domination, Beguile, Precog, or Clairvoyance. A Jacked Ganglionic Teleprojector is comparable to Domination. The rate of Charge Generation does not overtake the Biodynamic Power Plant (True Kin Cybernetic) until somewhere around Experience Level 50 and 32 Willpower.

Cooldown: 100 rounds (20)
Duration: (4 + Mutation Level * 2) to (13 + Mutaiton Level *2 ) rounds
Disables all robots, technology, and artifacts within the area.
DOES NOT disable artifacts worn and wielded by the player*.

Level 1: Radius of 2, 5x5 area.
Level 5: Radius of 5, 11x11 area.
Level 18: Radius of 9, 19x19 area.
Level 36: Testing Needed.

For comparison, the EMP Mk III grenade has a stun duration of (Testing Needed) and a radius of (Testing Needed), weighs one pound, and disables your artifacts if you are caught in it's radius. All grenades require a turn to place in your Throwing slot if it isn't in your Throwing slot already. In an emergency, EMP grenades can be detonated inside your inventory without being thrown.

The best 2 point mutation I never take. By Mutation Level 10 and Willpower 32, the stun duration on robots is longer than the cooldown. Defeating even Chrome Pyramids and Leering Stalkers - and collecting their endgame loot drops - becomes trivial**.

If RAs are able to increase the radius past 9, then this mutation is worth using RAs on. If not, then there is no point in levelling Electromagnetic Pulse past level 10.

In the early game, this mutation is nearly useless due to a lack of robotic and technology using enemies. In the late game, this mutation lets you trivialize the biggest late game menace: robots. Even if you manage to make peace with the Robot faction, there will still exist PlayerHater Robots such as Extradimensional Robots.

*Electromagnetic Pulses released by Clones and Temporal Fugues will still disable any of your gear that hasn't been modified to resist EMP.

**Robots can still kill you from outside your EMP range. Robots can instakill you before you have the chance to see them coming. Just because you can stun a robot indefinitely does not make it a sitting duck - it is a heavily armored sitting duck that requires late game gear to kill.

Damage: (Mutation)d4 + 1 Fire Damage*
Heat Increase: 315 + (Mutation * 25) Degrees
Range: Ray, 9 squares
Cooldown: 10 rounds (5)

Level 1: 1d4+1 damage, +340 Degrees.
Level 18: 10d4+1 damage, +565 Degrees. (Melts walls into lava.)
Level 36: 19d4+1 damage, +790 Degrees. (Super. Hot.)

Melee attacks increase enemies heat by +1d4 degrees (?) per hit.

Damage: Each MP increases damage by 1d4, or 3d4 per RA. Once you hit a cooldown of 5 turns, that's an absurd quantity of damage that nothing else in Qud comes close to*, even before you start setting things on fire and turning the walls into pools of Lava.** Although the burst damage is about half that of Electrical Generation, it has about a quarter of the cooldown and does bonus damage by setting things on fire.

There are, ah, one or two tiny drawbacks. Piles of ash can't be butchered for cooking ingredients. If a Ray passes through any items, they will turn to ash - even the ultra rare endgame items that were allegedly forged in the heart of dying stars.

There's also the tiny detail that Fire Immunity is the most common damage immunity out there.
Magma Crabs, for example, are completely immune to heat. They are also quite dangerous.

*Late game Espers can create suicide bombers using Hand-E-Nukes and Domination, but that's a level of damage extreme enough to instantly kill everything on an entire map tile.

**You can melt walls into Lava, pour the Lava into Thermodynamic Cells, then use those cells to power a Freeze Ray. Don't forget that you can pour the Lava in your Thermodynamic Cells directly on an enemies head. If an Esper, you can use Force Bubble, Stunning Force, or Domination to push people into Lava.

Damage: (Mutation)d3+1 Cold Damage
Temperature: -120 - (Mutation * 7)
Range: 9 tiles, Ray
Cooldown: 20 rounds (5)
Melee attacks cool enemies by -? per hit.

Level 1: 1d3+1 damage, -127 Degrees. (Freezes most enemies for at least one turn.)
Level 18: 10d3+1 damage, -190 Degrees. (Freeze if not instantly shatter most enemies.)
Level 36: 19d3+1 damage, -253 Degrees. (Cold enough to destroy many items.)

Mutually Exclusive with Burrowing Claws and Flaming Ray

Similar to Flaming Ray, except it sacrifices a small amount of firepower in exchange for freezing enemies solid, is less likely to destroy items on the ground, requires more willpower to bring the "cool"-down*, and fewer enemies are immune to cold.** The only reason to take Flaming Ray would be that RNG didn't give you Freezing Ray.*** Each RA not only adds 3d3 damage, but the extra -28 of cold keeps enemies frozen longer, and even kills some things instantly.****



*Not sorry.

**The few enemies that are immune to Cold can't take the Heat, and there are a LOT of gadgets out there that pack some Heat.

***Arguably, the Freezing Rifle is the most powerful ranged weapon in Qud - and it's basically equivalent to a Mutation Level 1 Freezing Ray. It only does 1d3 damage, but if you get an enemy cold enough, their bodies shatter.

****This is where I'd normally joke about Espers being OP, but unless the Esper is an Extradimensional with Cold Immunity, Freezing them solid in a single hit is the best way to deal with them.

Detection Radius: (3 + Mutation Level * 2)
Detection Radius: Entire Screen at Mutation Level 10

Level 1: Radius 5.
Level 18: Hear every creature on the entire screen.
Level 36: No significant benefits.

MP Cost at Chargen: Same as Clairvoyance.
Mutation Level that sees entire screen: 10, same as Clairvoyance (?)
Can it see items? No, unlike Clairvoyance.
Does it provide vision for teleport and LOS abilities? No, unlike Clairvoyance.
Can you identify what creatures you are hearing? Not instantly, unlike Clairvoyance.

Can it detect invisible creatures? YES! Clairvoyance cannot detect Invisible Creatures!

...

There is only one invisible creature in all of Qud.

...

It is a pushover.

Level 1: +15 Quickness (one bonus round every 6-7 rounds)
Level 18: +33 Quickness (one bonus round every 3 rounds)
Level 36: +51 Quickness (at least one bonus round every 2 rounds)

Extremely good. Low key one of the best mutations, even if it isn't flashy or exciting. +15 Quickness means +15% to your attack speed and DPS AND +15% to how often you move. Even at level 1, that's extremely good, and it only gets better with more RA's. It helps you out-DPS enemies with high armor and regen, while also letting you out-run pretty much everything.

High synergy with anything that has a chance to trigger on normal attacks, such as Stinger, Horns, and Double Muscled. Very high synergy with anything involving movement, like Multiple Legs, Spinnerets, and Wings. Extremely high synergy with Adrenal Control and Photosynthetic Skin, as bonus rounds don't count against the duration of buffs (including those from cooking). See the sections on Adrenal Control and Photosynethic skin for more details on quickness synergy.

That said, there are a few things Quickness does NOT do.

Cooldowns such as from Flaming Ray are not affected by bonus rounds.
Charges such as from Electrical Generation are not affected by bonus rounds.
Once/round abilities like Corrosive Gas generation won't generate gas on bonus rounds.
Once/round damage such as from Corrosive Gas or Poisonous Stinger only trigger once per round.
Passive health regeneration does not occur on bonus rounds, only normal rounds.

Any build that depends on abilities with cooldowns or DOT will have weak synergy with Heightened Quickness. Don't get me wrong, quickness is still incredible without synergy, but please keep in mind that the usefulness of most mutations varies greatly depending on your build.

Horn Damage: 2d(RoundDown(Level/2)+3)
Armor Bonus: RoundDown((Level – 1)/3) + 1

20% chance on ANY melee attack for a bonus horn attack, which may cause bleeding.
If Horns are the primary weapon (switch primary limb in inventory screen), 20% bonus horn attack is replaced with using Horns as a primary weapon.
The Charge skill automatically hits with the Horn.
Cannot wear Helmets.

Level 1: 2d3 damage, 1 AV. (Carbide Tier)
Level 18: 2d8 damage, 4 AV. (Zetachrome Tier)
Level 36: 2d12 damage, 7 AV. (Two Handed Zetachrome Tier)

Horns: Surprisingly good in the early game, but it has similar problems as Burrowing Claws. All the damage in the world won’t help if you lack the Strength to penetrate armor or Tinkering to bypass armor with Masterwork. Being unable to wear helmets prevents two gamebreaking options in the late game.

Horns are shortblades, and benefit from dagger skills like Jab.

4 Multiple Arms (B)

Bonus Attack Chance: 7 + Level * 3
Two extra Arm slots
Two extra Hand (weapon) slots
One extra Hands (glove) slot

On ANY melee attack, each of the two extra hands have a chance of making a bonus attack.
Jab (Short Blades) and Flurry (Dual Wield) DO apply to Multiple Arms.

Level 1: 10% Bonus Attack Chance, 5 extra equipment slots
Level 18: 37% Bonus Attack Chance
Level 28: 53% Bonus Attack Chance
Level 36: 64% Bonus Attack Chance

An A Tier mutation at level 1, but it's rarely worth dumping RA’s into. The extra arms can hold bucklers and gadgets, the extra hands can hold shields or serve as the second hand for two handed weapons, and the extra pair of gloves can be tinkered for elemental resistance or stat boosts. If you have Flurry, that guarantees an attack from all limbs regardless of mutation level - all at Level 1!

To get reliable bonus attacks, you need either Jab and 2 RA’s into Multiple Arms, or a total of 7 RA’s to reach a 100% attack chance with the bonus limbs. This is still a reasonable investment if your build relies on bonus attacks to deliver stun locks (Cudgel) or dismemberment (Axe), but far from gamebreaking.

Bonus Move Speed: Level * 20
Bonus Carry Weight%: Level + 5
Extra Feet Slot (Boots)

Level 1: +20 move speed (1 bonus move ever 5 moves), +6% Carry Weight
Level 18: +200 move speed (2 bonus moves every 1 move), +15% Carry Weight
Level 36: +380 move speed (~4 bonus moves every 1 move), +24% Carry Weight

As with Multiple Arms, the greatest benefit is at level 1. An extra feet slot allows shennanigans like using Rocket Boots and AntiGravity Boots at the same time, in addition to stacking tinkering mods like Wooly for more heat/colst resist. Unlike Multiple Arms, the benefits of the extra RA’s don’t require a specific melee build, and scale into the endgame.

The greatest threat in the lategame of Qud are the infamous enemies that can instakill you on the same turn you see them. However, if you see these enemies on a BONUS move instead of a REGULAR move, you get a “free” turn to react as they can’t move until you take your next REGULAR turn. At Mutation Level 19, possible at Experience level 36, nearly 80% of your moves will be BONUS moves!

Keep in mind that "Bonus" moves are NOT regular turns. Corrosive Gas Generation, for example, won't emit any gas on bonus moves - only on regular turns. More move speed won't increase your DPS (outside the Hook And Drag skill in the Axe skill tree).

I can’t think of many late game threats that can’t be trivialized by positioning, kiting, or running away, and this mutation helps you do all of that – without any cooldowns whatsoever! If this somehow isn't enough speed on you, Sprinting DOUBLES your already insane move speed. I can say from experience that this is low-key one of the best mutations in all of Qud, even if it isn't as "shiny" as the S tier stuff.

Note: The Hindren of Bey Lah are one of my favorite long term Proselytizing Pets, specifically because they have this mutation. The extra move speed means they take a lot less damage while approaching ranged foes.

Duration: Level + 6
Cooldown: 100 – (Level * 3)

Level 1: Duration 7, Cooldown 100 (20 at 32 Willpower)
Level 18: Duration 16, Cooldown 73 (~15 at 32 Willpower)
Level 36: Duration 25, Cooldown 28 (~6 at 32 Willpower)

Note: Cooldown does NOT start until AFTER Duration ends, so Phasing 10 doesn’t let you stay permanently phased. If you want to remain phased while the Phase mutation is on cooldown, you’ll need to manually detonate a Phase Grenade in your inventory or rely on the finicky Shade Oil tonic.

You get most of the benefits at Level 1. Bypass any door. Use Phase+Sprint to get to the stairs. Apply a Salve Tonic or a Blaze Injector. Eat an Urberry. Take off your boots, put on Ninefold Boots, replace the energy cell, and outrun anything – with a few rounds of Phase to spare. You don't need a single RA to make this mutation A tier.

The only appeal of investing RA’s into Phasing is the ability to damage enemies while you are still phased. This can be done with Phase Harmonic guns, the Phase Cannon, and grenades tinkered to be Phase Conjugated. Sadly, even with a phase duration of 25, you won’t be able to kill anything dangerous in a single use of Phase. Grenades deal more damage, but are more expensive and can kill or at least freeze enemies within the 7 rounds of Phase 1.

Bask Duration (in Days): 1 + (Level – 1)/4
Regeneration: 20 + (Level * 10)
Quickness: 13 + (Level * 2)
Max Servings: 1 + (Level – 1)/4

Gain a Serving of Starch and Lignen every 6 hours (300 moves) on the surface during the day.
Cook with Starch and Lignen at a campfire to gain the Bask bonus while underground.
Become vulnerable to Defoliant Gas due to being plant-like.
WARNING: Receiving ANY form of damage stops ALL natural healing for 5 turns, unless you have the Regeneration mutation. By itself, Photosynthetic WILL NOT heal you during combat!

Level 1: Bask 1 day, +30% regen, +15 quickness, 1 serving.
Level 18: Bask 3 days, +120% regen, +33 quickness, 3 servings.
Level 36: Bask 5 days, +210% regen, +51 quickness, 5 servings.

Most of the benefits are at level 1, with +15 quickness and +30% regen whenever you Bask or cook with Starch and Lignen. Limited usefulness unless combined with Regeneration (heal during combat), Heightened Quickness (stack quickness), and Adrenal Control (which boosts all of the above mutations, in addition to quickness). Note that using Adrenal Control right before basking or cooking with Starch and Lignen gives you the boosted version of Photosynthesis for the entire day.

The usefulness of Photosynthetic varies drastically depending on your mutations and playstyle. If you have Regeneration and Adrenal Control, you want to dump the RA’s in Adrenal Control instead. If you have just Regeneration, dump RA’s into Photosynthetic. If you have just Quickness, you’re better off dumping the RA’s into that instead. If you have escape tools like Phasing, Forcefield, or gadgets with similar effects, you might want the RA’s in Photosynthetic. If you spend a lot of time caving and/or prefer cooking with ingredients other than Starch&Lignen, this mutation is an obvious waste.

As I said, it’s usefulness varies drastically. At best, A tier. At worst, D tier.

For reference, there are common cooking ingredients that grant +100% regen and +15 quickness. If you like regen and quickness, you can get the benefit of Photosynthetic 9 regen and Photosynthetic 1 quickness without this mutation.

Healing Bonus%: 10 + (Level * 10)
Limb Regen Chance: Level * 10
Remove Physical Debuff Chance: 1 + RoundDown(Level / 3)
Receiving damage DOES NOT prevent natural healing. (Normally, receiving any form of damage stops natural healing for 5 turns.)

Level 1: +20% regen, 10% chance of limb regen per turn, 1% chance to remove debuff.
Level 18: +110% regen, 100% limb, 4% debuff chance, immunity to Decapitation.
Level 36: +200% regen, 190% limb, 7% debuff chance. (NOTE: if limb regen chance is over 100%, there is a chance to regenerate multiple limbs in a single turn.)

Most of the benefit is at level 1, which stops combat from interrupting passive healing. At level 10, it grants immunity to decapitation and rapid limb regeneration. After that, each RA in Regeneration only grants +30% regen (compared to +60% regen per RA in Photosynthesis).

There is no good reason to dump RA's into this mutation for one simple reason: The humble Salve Tonic. 0.6*ExperienceLevel per round for 5 rounds adds up to 3*ExperienceLevel total healing. At level 36, that's 36*3=108 healing - more than an Urberry. With the Juicer skill, apply two Salve tonics for 208 healing over 5 turns. In the late game, Salve tonics are cheap and plentiful.

By comparison, at Experience Level 36, 32 Willpower, and 32 Toughness, natural healing will be (20 + 2 * (8+8))/100 or 52/100, or 0.52 hit points per turn. That's ~6 HP over 5 turns. Regeneration 19 improves that to an impressive... ~1.5 HP per turn, or ~18 HP over 5 turns.

Get Regeneration to 10 ASAP to prevent decapitation insta-kills, but don't waste RA's to pump it any higher.

Quill Penetration: RoundDown((Level - 1)/2) NOTE: Penetration cannot exceed 6.
Quill Regeneration Rate: Level * 0.25 NOTE: Modified by up to +80% at 32 Willpower.
AV Bonus if >=50% Quills: RoundDown(Level / 3) +2
AV Bonus if =<50% Quills: RoundDown(Level / 2)
Cannot Wear Body Armor
Immune to Quill Damage
Mutually Exclusive with Carapace
3% Damage Reflection, but lose 1% of quills when attacked in melee.

Damage to 1 Target: (Current Quills × 0.10 / 8)d3
Total Damage (if surrounded by 8 enemies): (Current Quills × 0.10)d3


I won't bother doing the math on this one. You should be able to understand how utterly non-broken and underwhelming this mutation is just by looking at the formulas. Bad damage progression, capped penetration can't hurt late game threats, poor AOE compared to all other AOE abilities, immunity to a rare and underwhelming mutation, can't wear tinkered body armor, quills regenerate slowly...

Sure, with enough RA's it has more AV than Zetachrome armor, but you can theoretically get infinite AV from Neutron Flux. It's a bad trade no matter how I look at it.

The only way to wind up with this mutation is random character creation or Irritable Genome. I can't think of any mutations worse than this. That said, I've never tried it, so there exists a small chance it has some hidden redeeming quality I missed.

20% Chance on ANY melee attack for a Bonus Sting.
If the Stinger is the primary limb (from equipment menu, use Tab to change primary limb), replace the 20% Bonus Sting chance with a 20% chance to apply the special effect of the stinger.

ALWAYS Sting on Charge (Tactics) or Lunge (Long Blades).
The Stinger is a Long Blade.
The "Sting" Ability can be activated to guaruntee a hit and penetration, in exchange for being unable to Sting (Bonus Sting or otherwise) for 25 rounds (5 rounds at 32 Willpower).

Penetration: ((Level - 2) / 3 + 4) + 4 NOTE: Minimum of 2, maximum of 13 (at 3 RA's).
Save Difficulty (Toughness): 14 + Level × 2

If the Stinger penetrates and the save is failed, the target suffers from the following, depending on the type of Stinger:

Confusion for a duration of: 2d3+((Level × (2 / 3)) + 2 ) NOTE: Minimum of 2d3+2, max 2d3+14.
Confused enemies move and attack in random directions. This reduces their chance of hitting you to almost 0, but makes them annoying to chase down.

Paralyze for a duration of: 1d3+((Level / 3) + 1) NOTE: Maximum of 1d3+7.
Paralyzed enemies are... paralyzed. This renders them harmless. Paralyzed enemies can be stung repeatedly, resulting in a a perma-stun.

Poison Damage Increment: (Level)d2
Poison Duration: 8-12 rounds, or ~10 rounds.
Poisoned enemies receive an impressive amount of damage, in addition to preventing natural healing and halving the usefulness of healing items.

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Level 1: 7 penetration, 1d6 damage (Carbide), 16 save.
2d3+2 rounds of confusion, 1d3+1 rounds of paralysis, or ~10d2 damage over 10 turns.

Level 18: 10 penetration, 1d12 damage (Zetachrome), 34 save.
2d3+8 rounds of confusion, 1d3+4 rounds of paralysis, or ~100d2 damage over 10 turns.

Level 36: 13(?) penetration, ? damage, 52 save.
2d3+13 rounds of confusion, 1d3+7 rounds of paralysis, or ~190d2 damage over 10 turns.

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The TL;DR is that all Stingers are equal, but some Stingers are more equal than others. Jokes aside, all of the Stingers are amazing. Confusion makes chasing down dizzy enemies annoying, but also renders renders enemies harmless for the longest duration of all the Stingers. Paralysis is less annoying, but you probably won't be stunning more than two enemies at a time. Poison aka Venom does an absurd amount of damage unmatched by ANY weapon, period.

The best part? Combine Stinger with Dual Wielding, Short Blades, Multiple Arms, Horns, Quickness, Wings (increase the range of Charge, which automatically Stings on hit), a certain "cape" dropped by a certain miniboss... and you will be throwing out so many Stings that you would swear the odds of proccing it are greater than 20%.

Worth putting RA's into for one reason: The Save difficulty. Endgame enemies have high Toughness, and will be immune to the Stinger unless you increase the Save difficulty. Even after you max out the duration of Confusion and Paralyze with 3 RA's, you can still dump more RA's into them. The damage of Poison keeps going up no matter how RA's you dump in it.

You might be wondering which Stinger is B tier and which one is S tier. Honestly, it's a matter of opinion - I could make an argument for any of the stingers being B tier, A tier, or S tier.

WARNING: Non biological enemies, such as ROBOTS, are immune to the special effects of Stingers. Luckily, they can be trivialized with enough EMP grenades and Resonance grenades.

Cooldown: 35 rounds (7 rounds at 32 Willpower)
Duration: Level + 2 rounds
Density: 800 units per round, or 100 units in each adjacent square if surrounded by 8 empty squares.
Save (Toughness): 5 + Level + (Density / 10)
Sleep Duration: 4d6 + Level

Note: Save difficulty decreases as gas density decreases.
Note: Gas takes awhile to disperse, long after the duration of releasing gas ends.
Note: Enemies that do not breath, such as ROBOTS, are immune to sleep gas.
Grants immunity to sleep gas (NOT immunity to sleep NOT caused by gas).

Level 1: 3 rounds, save of 1
Level 18: 12 rounds, save of 10
Level 36: 21 rounds, save of 19

I haven't tested sleep gas in the late game, but it's incredible in the early game. Since enemies must attempt to save against sleep EVERY turn the are in the gas, the chance of making enemies fall asleep is much higher than the duration and save difficulty would indicate. Due to how the Density of gas affects the save, enemies adjacent to the player after multiple rounds of releasing sleep gas may face a save difficulty 10 times higher than normal, or more - keeping sleep gas relevant in the late game.

Oh, and the cooldown is a mere 7 rounds at 32 Willpower. In the late game, spreading a blanket of sleeping gas across the entire map is a trivial affair. If that ain't OP, I don't know what is.

Doesn't work against robots, so hopefully you have some EMP grenades.

Cooldown: 80 rounds (16 rounds at 32 Willpower)
Duration: Level + 5
Save Bonus vs Forced Movement: Level +5

Save Difficulty to Escape Webs: 14 + (Level * 2)
Escape Phased Webs: 18 + (Level * 2)

Max Weight held by Webs: 120 + (Level * 80)
Weight by Phased Webs: 520 + (Level * 80)

1: 6 rounds, save of 16, weight of 200
18: 15 rounds, save of 34, weight of 920
36: 24 rounds, save of 52, weight of 1520

Note: Grants immunity to not only Webs, but getting stuck in Honey and Asphalt as well.
Note: If you let Phase webs "mature" for a few hundred turns, you can collect Phase Silk from them (then cook Phase Silk to temporarily gain the Phase mutation, to repeat the process.)
Note: Enemies stuck in webs suffer a -10 DV penalty.

I honestly haven't used Spinnerets much. If you have Phasing, you can make Phase Webs, get enemies stuck while Phased, then unphase to escape from them. Some people recommend web forts that surround deployed turrets (Tinker). It's a great escape tool vs melee enemies. Great synergy with Multiple Legs, Quickness, and anything else that grants speed - after all, EVERY movement during the duration drops a web, but BONUS moves don't count against the duration IIRC.

YMMV. On this one. It's situationally powerful, but tricky to use. Even if it's not the best mutation, the idea of creating a "Zoo" of permanently stuck enemies using webs with impossibly high save difficulties is hilarious.

Bonus Agility: 2 + RoundDown(Mutation - 1) / 2)
Free Skill Chance: 7% + Mutation Level * 3

Level 1: +2 Agility, 10% chance that an agility based skill has no cooldown.
Level 18: +6 Agility, 37% chance that an agility based skill has no cooldown.
Level 36: +11 Agility, 58% chance that an agility based skill has no cooldown.

Don't get me wrong, the agility is good. Every 2 agility gives +1 to hit and +1 to dodge nearly every attack in the game, both melee and ranged. Still, stats can be farmed elsewhere with some difficulty.

The chance to use Agility Skills with no cooldown is the real benefit. How good are Agility Skills? Here's a list:

Flurry (Dual Wield): Attack with all organic limbs, including limbs granted by mutations (Multiple Arms, Stinger, Horns, bonus limbs from Chimera).

Lunge (Long Blade): Depending on Stance, charge forward one space, dodge back two spaces, or GUARANTEE a penetrating hit.

Empty The Clips (Pistol): The action cost of firing pistols is halved. Ie, fire rate is doubled. This is on top of all the passive pistol skills that improve fire rate.

Hobble (Short Blade): Provided you don't miss, penetrate once and inflict a movespeed debuff.

Shank (Short Blade): If you don't miss, gain +2 Penetrations per debuff on the target. (Ie, a 1d6 Carbide Dagger against a Bleeding opponent does 3d6 damage. A 1d12+2 Zetachrome Dagger against a Bleeding, Hobbled, Dazed, Poisoned opponent takes 9d12+18 damage. But wait, we can do better - there are 18 negative status effects, and we haven't Tinkered the Zetachrome Dagger yet...) A Willpower of 26 brings the 10 round cooldown down to 5 rounds, but what would happen to your DPS if there was no cooldown at all?

Juke (Tactics): Move one square instantly. Combine with Pointed Circle (Short Blades) to get a free attack every time you use Juke to swap squares with an opponent. Combine with Bloodletter (Short Blades) for a 100% bleed chance on Juke attacks. The only think keeping you from pulling a Za Warudo* and killing everything on the map, instantly, is the cooldown...





*Possible at Experience Level 65. Mutation Level 10 + 3 * 7 RAs = Mutation Level 31. Getting to level 50 is extremely difficult and tedious, but not unheard of. I think level 68 is the highest that any credible accounts have reported.

Mental (aka Esper) action cost reduction% of: 15 + Level * 5
Remove mental debuff chance% of: 5 + Level * 2

Mental debuff removal chance is applied instantly when the debuff is first received, AND each subsequent round. Stacks with skills.

Level 1: 20% Esper action cost reduction, 7% mental debuff removal.
Level 18: 65% Esper action cost reduction, 25% mental debuff removal.
Level 36: 100% Esper action cost reduction, 43% mental debuff removal.

Most of the benefit comes at Level 1. If you get Decapitated, you still have an extra head (unless you got hit by a flurry of Decapitates, in which case you're still dead). If you got cursed with Horns, you have an extra head that can wear a helmet. If you have Psionic Migraines, you're an <CENSORED>. If you are a normal mutant, you can now wear TWO helmets, tinker both of them to be Two Faced, and get a +6 ego boost from early game gear, or a <REDACTED> immunity from late game gear.

That's a lot of benefits at level 1, without needing to add a single RA.

That said... if you are going all in are Esper abilities... 100% action cost reduction to Esper abilities is pretty nice. The only way to improve the Clairvoyance, Temporal Fugue, Mass Mind, Temporal Fugue, Teleport combo - is to do so before spending a single turn.

Toughness: RoundDown((Level - 1) / 2) + 2
Sprint Duration Bonus%: 20 + Level * 10

Level 1: +2 Toughness, +30% Sprint Duration
Level 18: +6 Toughness, +120% Sprint Duration
Level 36: +11 Toughness, +210% Sprint Duration

Meh. Stats can be farmed without spending precious mutation points. You get a decent amount of HP from experience levels even with mediocre toughness (most recommend 18 at chargen) Sprint duration is nice, but unless you combine it with something that improves Sprint speed, (Wings, Multiple Legs, Quickness, Etc), it's a questionable benefit compared to the more powerful escape tools like Wings+Jump, Phase, etc.

If you've sworn off stat farming, the extra HP is definitely a mid game lifesaver. You gain 1d4+Toughness Modifier HP per level, so a mere +2 Toughness Modifier (or +4 toughness from Two Hearted) doubles grants +100% HP compared to your base HP at 16 toughness. That said, no amount of HP will save you from the late game insta-kills, debuffs, temperature penalties, etc.

Not a terrible mutation, it's just not good. Has good synergy with Wings, but in that case you should dump RA's into Wings instead.

World Map Travel Speed 1.5 + ( 0.5 × Level )
Lost Chance Reduction ( 36 + ( Level × 4 ) )% maximum 95%
Movement Fall Chance ( 6 - Level )% minimum 0%
Swoop Fall Chance ( 24 - Level )% minimum 0%
Move Speed while Sprinting ( ( 0.1 × Level + 0.1 ) × 100 )%
Jump Distance Bonus 1 + ( Level / 3 )
Charge Distance Bonus 2 + ( Level / 3 )

NOTE: While Flying, you can escape to the overmap EVEN WHILE SURROUNDED BY ENEMIES!

Level 1: 5% chance to fall while flying, 23% chance when swooping, +20% sprint speed, +1 jump range, +2 charge range.

Level 18: 0% chance to fall while flying, 14% chance when swooping, +110% sprint speed, +4 jump range, +5 charge range.

Level 36: As above, 5% fall chance when swooping, +200% sprint speed, +7 jump range, +8 charge range. (Note: A total of 5 RA's is needed to bring the fall chance when swooping down to 0%.)

At Level 1, use a ranged weapon - which has a 0% chance to make you fall when you attack with it. As long as you don't move, (and don't get hit by ranged or freezing attacks) there shouldn't be any risk of falling, even at Level 1. REMEMBER THAT YOU CAN FLY to escape to the overmap EVEN WHILE SURROUNDED BY ENEMIES. You get all this without investing a single RA.

Wings also grants a bonus to overmap travel speed and reduces the odds of getting lost... but that's kind of irrelevant by the mid game.

While underground, the benefit of Wings is 3 fold: Increased Sprint speed, enhancing everyone's favorite lifesaving ability. Increased Jump range, which is basically the poor mutants Teleport. Finally, the Charge range lets you get into melee before enemies with guns can do much damage.

Each of these abilities isn't that exciting on it's own, but combining them all into a single mutation is a pretty decent package. I should probably rate this mutation as a B, but I'm bumping it up to A because wings are cool.

I apologize for the lack of comments. I lack the patience, maturity, and time to moderate such things - indeed, it is with great difficulty that I refrain from adding more than one joke to this guide.

I will probably be too lazy to update this guide, so feel free to plagiarize and improve this guide as you wish. No credit necessary. As long as useful information on this rapidly - updating game are accessible to new players, that's all I care about.