In the Yoruba religion of Benin, a kokou is one of the most highly feared warrior under gods. It is the most violent and powerful of the Yoruba spirits. The voodoo rituals surrounding it involve its followers falling into a deep trance with rapidly beating drums.
Once possessed by the spirit, the body in which the kokou inhabits may remain in a trance all day and in due course demonstrate a thirst for blood with glass, bottles and knives, swallow sharp objects or repeatedly beat its head against the wall until it bleeds profusely, revealing a high tolerance to pain.