Jockey

The Jockey is a type of Special Infected that appears in Left 4 Dead 2. It appears as a squat man with a sizeable hunchback, a lipless mouth and bloodied hands and feet. It constantly laughs maniacally, even when not attacking prey. The Jockey moves like a monkey and is frightfully agile, and uses these qualities to ambush survivors from behind, pouncing from the shadows and grabbing onto a victim's back. Once on a person's back, the Jockey will grasp, scratch and even hump its victim as they struggle to shake it off. It will attempt to "steer" its victim into danger, directing them towards other Infected so that the other members of the horde can kill the survivor.