Umcherrel, the Soul of the Forest
If a shaman successfully powders up and inserts into various orifices the mystic mushroom, partakes of the sacred toadstool, smokes sufficent of the holy rhizome, then whilst sitting crosslegged under a pine tree is not distracted by blue four-sided triangles pin-wheeling across his visual field , and can prevent the top of his head from unscrewing and drifting away, he may then see the god Umcherrel, the very living Soul of the Forest. This earns him the title of "Spirit Master". Other gods that may be seen include Topaxci, the God of the Red Mushroom and Skelde, Spirit of the Smoke. Seeing either of these will entitle the shaman to a different title.
Mentioned in The Light Fantastic.