Why Headcrabs Are So Terrifying - Half-Life: Explained 

In this video I explain the headcrabs and zombies from the half life series. We cover the wide range of different zombies you can encounter throughout the series.
I used the Headcrab+ mod for Garry's Mod to gather the footage of what headcrabs would act like in reality. In-game, they do not infect anybody unless it is scripted.
I'm also aware that I didn't cover the lightning dog/headcrab, this technically isn't a headcrab and will be getting its own video.
==In This Video==
Music: "Darren Curtis - It's In The Fog" is under a Creative Commons license (CC BY 3.0).
/ darrencurtismusic