A headcrab is a fictional alien parasitoid found in the Half-Life video game series created by Valve Software. They are the most numerous and arguably most iconic aliens in the series. They are also sometimes referred to as "headhumpers" by Barney Calhoun and some of the citizens in the game.
Headcrabs are parasitic life-forms roughly 2 feet (0.61 m) long. Headcrabs have...
