In the Yoruba religion of Benin, a Kokou is one of the most highly feared warrior Undergods. It is the most violent and powerful of the Yoruba spirits and the voodoo rituals surrounding it involves its followers to fall 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 profusively, revealing a high tolerance to pain.
One who fails to respect the Kokou during a ceremonial trance may have a sacred calabash placed on his head until it becomes excessively heavy.
- Butler 2006, p. 32.