Spycrabs. That's it.

At the time of year where temperatures start dropping, the spycrab will start congregating to the warmer areas. There reason of choice is to prevent cryolation of their fragile bodies, as they will suffer a cold, painful death otherwise.
Observe the spycrabs in snowplow, forming bunches to transport their brethren safely. As they move towards the hotter regions, such as lakeside, this will become more important due to the abundance of gibus engies and pyrosharks. Our role in this is to escort the spycrabs to fend off the enemies that have a thirst for juicy spycrab. Some spycrabs will choose to protect themselves with a cardboard box. This will confuse sentries and cause them to shoot in random places.