These little buggers can freak players out. Mainly a nuisance, but they are hard to target.
Fast Headcrab
Very fast version of a normal headcrab. It is more prone to leap at you then the others. Can be really hard to shoot.
Poison Headcrab
These guys are very annoying. If they hit you they will poison you. The thing is, it cannot kill you by itself. It's the only enemy in the game that can't directly kill you.
