Cosmic Clowns is an ethnographic analysis of how the Chapayeka is created as a figure, how their performance is constructed, and what part they play in the dynamics of the ritual. The Chapayekas combine two kinds of performance: they perform set, conventional actions and improvise and invent new actions. This creates dialectics of invention and convention that allow the figure to mediate between the ritual and its context and different kinds of beings within the Yaqui cosmology. Cosmic Clowns offers a new perspective on tricksters and clowns and shows how they are characterized by constant alternation between invention and convention; this is what connects them to the collective and moral aspect of culture and, at the same time, makes them unpredictable and powerful. This study shows that it is possible to do justice to the opposed aspects of these ambiguous and paradoxical figures by taking into account the different foundations and contextual effects of the different modes of symbolization.