Yakashukuma is one of the great monster-spirits, or apapanye, that inhabit the rivers and lagoons of the Mehinaku world. To the ordinary eye it appears as a caiman, but it is a man-animal: when it steps out of its caiman skin and turns its star-eyes upon a person there can be no doubt that one stands in the presence of a denizen of the spirit world. Like the other apapanye it is a maker and owner of the beings among which humans live, and contact with it brings dangerous illness. Shamans mediate such afflictions, and the spirit's likeness enters the round of masked festivals through which the Xingu peoples honor and hold at bay the powers of the water.