In-game "Help Headbutt": Headbutt allows you to use your head as a smashing weapon, knocking your foe on his noggin and stunning him briefly while he regains his senses. It does a minimal amount of permanent damage; its benefit is in making your enemy stop fighting while he recovers. This skill requires combat. If your opponent is already down then there's a pretty good chance you'll trip over them.
Headbutt is the most widely used and coveted skill in the Worlds of Carnage. Headbutt allows you to deal extra damage on the victim while they are unconscious. This skill will allow a fighter to stun the opponent for multiple combat rounds and deal great damage while the opponent is not hitting back. Try not to intitiate your next headbutt until your opponent is standing up, otherwise you'll fall flat on your face for the duration of the headbutt lag.