Iconographic studies often provide evidence to interpret ritual activities of archaeologically known cultures. Recent excavations at the site of Conchopata near Ayacucho, Peru, led to a re-analysis of the ritual behavior of Middle Horizon (A. D. 750-1000) Wari society. The identification of a hallucinogenic plant design, Anadenanthera colubrina, depicted on Conchopata offering pottery contributes a crucial understanding of a previously unknown artistic icon. This icon was discerned as depicted in various abstract renditions on Middle Horizon textiles, snuff paraphernalia, ceramics, and stone sculpture, including the Gate of the Sun at Tiwanaku, Bolivia. Based on historic and ethnographic evidence, the plant's prehistoric use as a hallucinogen is discussed with regard to suggested chicha drinking ceremonies, and the transitional role of Wari leaders from shamans to priests.