a stereotypical UFO?

perhaps an ornithopter like the ones from Dune?

a KV-2 that has a lot of recoil when you shoot, because i can see that being proper hilarious.

maybe something with legs, as in like a spider like machine, I'm not too sure what those are called?

a massage chair that heals you?

a close range mech that has a flame thrower (idk how you would pull this off, but hey good luck!)

I've seen you play piano on youtube, you could make flying piano that flashbangs people? i doubt that idea would fit the theme though.

however, i think this one wins out;
T sided SHOPPING CART with a machine gun, doesn't that sound amazing?

a mech with icmbs that walks around