Demonic possession is held by many belief systems to be the spirit possession of an individual by a malevolent preternatural being, commonly known as a demon. Descriptions of demonic possessions often include erased memories or personalities, convulsions (i.e. epileptic seizures or “fits”) and fainting as if one were dying. Other descriptions include access to hidden knowledge (gnosis) and foreign languages (xenoglossy), drastic changes in vocal intonation and facial structure, the sudden appearance of injuries (scratches, bite marks) or lesions, and superhuman strength. Unlike in channeling, the subject has no control over the possessing entity and so it will persist until forced to leave the victim, usually through a form of exorcism.