Alleged belief in a Great Spirit 501 The great mystery a modern deity 501 Polytheism 502 Worship 502 Fasting 502 Sacrifice 502 The Okipa 502 The Daḣpike 503 Cult of the Yoni 505 Absaroka fear of a white buffalo cow 505 Mandan cults 506 Mandan divinities 506 Guardian spirits 507 Mandan belief about serpents and giants 507 Thunder lore of the Mandan 508 Astronomical lore 508 Mystery objects and places of the Mandan and Hidatsa 508 The mystery rock 508 Dreams 510 Oracles 510 Fetiches 510 Folklore 511 Sorcery 511 Jugglery 512 Ghost lore 512 The future life 512 Four as a mystic number among the Mandan 513 Hidatsa cults 513 Hidatsa divinities 513 Animism 514 Worship of the elements, etc. 514 Serpent worship 514 Fetiches 515 Tribal fetiches 515 Personal fetiches 515 Oracles 516 Dreams 516 Berdaches