Standard Headcrab: Just a standard headcrab. Latches onto a foes head and controls them. Poison headcrab: A black, big, venomous headcrab that latches onto someone's head, as more poison headcrabs latch onto their back. Very dangerous and durable yet slow and usually attacks once. Fast headcrab: A faster than normal headcrab that is more vurnerable. Vortigaunt: Resistance allied alien. Uses deadly Vortessence attacks that spark at enemies. Can speak English.
