From Burning Wiki
The Karuba bean is used by the people of Baru to enter into their trance-like states called vision callings. In a vision calling they are able to communicate with their animal-spirit. The bean resembles a hardened raisin, shrivelled and purplish brown in colour. It comes from the flowering Kara shrubs that grow along the outer edge of the evil forest. It is soaked in warm water before being pulverized and made into tea, a process of at least an hour. It is then drunk and the trance that follows can last up to 4 hours.