Biastophilia

A paraphilia (or sexually practice that is considered deviant or not socially acceptable) in which sexual arousal becomes dependent on sexually attacking a nonconsenting, surprised, terrified, and struggling stranger. This is a kind of rape even though most rapes are committed by normophilic men (men who's sexually practices are not considered sexually deviant...other than rape, of course). The main source of the sexual arousal is the actual fear, surprise, and resistance from the victim.