Just when you think you've got the hang of whacking normal headcrabs for six, they pull out the big guns. The crotchcrabs move and jump faster, are uglier and a tad more...deadly. You have to deal with the constant threat of one latching onto your crotch and turning you into a zombie. If they succeed in taking a victim, they will not only become a zombie, but the more deadly variant, the horny zombie.
The end result of a successful attack from a crotchcrab. Fundamentally the same as the standard zombie, only with one rather significant upgrade; the pelvic thrust. This means it's even more important that you try and keep your distance and put them down with a few well aimed headshots. Same rules apply though, if the body takes too much damage the headcrab will detach and attack you itself.
Fast Horny Zombie
Zombies are slow, right? That's their major disadvantage, right? They can't close the gap to get in a close range swipe before you fill them with lead, right? Wrong. This new zombie variant is the most deadly yet. Capable of insane speeds and an even more ferocious pelvic thrust, they will dryhump you in a blink of a Vortigaunts singular red eye. These mercurial monsters like to haunt old graveyards with their woods, leaping at their unsuspecting prey from trees and bushes. And as if that wasn't enough, they often hump in packs, so you will need to keep your wits about you when trekking through their territory.