Intelligence Crabs like to swim around the waters of 2fort, and it's sewers. They often attack foes when in danger.
They will often swim away when in the presence of a Pyroshark, or try to kill it. If killed, the Intelligence Crab will collect it's gas mask as a trophy.
When pregnant, female Intelligence Crabs build nests made of the papers from intelligence cases. They then lay eggs similar to chicken eggs.
When hunting, they will take their shotgun or bat and crawl to the Intel room and steal the Intel. If there are sentries, the crabs will wait and stalk the Intel. If they find a can of BONK!, they will jump on top of the sentry and kill both the sentry and the engineer. They often spare dispensers and teleporters. They will then take the Intel to their nest.
Rarely, an Intelligence Crab will travel to Doomsday maps and steal the australium Intel and run back to 2fort. They will melt the australium and pour it on their scatter guns.