Classic Teotihuacan's mural tradition evidences a Great Goddess and a Storm God in a cult of rain and fertility, yet their identity and relationship is problematic. This article reads the mural iconography as a myth of passage where the Great Goddess transited through portals uniting the planes of the cosmos at the boundary between the dry and rainy seasons to transform into the Storm God. Slate and pyrite mirrors and murals are analyzed as sacred artifacts with agency to invoke passage. The species of animals and plants symbolizing portals are identified to decode their symbolism of passage as symbolic transformations.
The Great Goddess transited from the underworld to the sea, entered mountain caves, and transformed her head-summit into a primordial cloud. The goddess created the axis mundi through her sacrifice, integrating the plants used for the manufacture of the Mesoamerican rubber olli. Mediated by the metamorphic powers of butterflies and olli, the goddess transformed greenstone into sacred water to become the Storm God. He commanded his helpers from his cave dwelling to produce rain and fertility clouds. Ruler-priests and warriors used mirrors to access the axis mundi and to transform into Storm God avatars with powers over rain and fertility.
