Witch's moss is a fungi local to Gramarye. It is especially responsive to projective telepaths who can mold it into almost anything (the only limits being the quantity of Witch's moss and the telepath's imagination). Witch's moss grows naturally and is descibed as being a silverish paste-like substance. it is known that if a creature of Witch's moss breeds the offspring will be true being, that is not of witch's moss. Though creatures made of witch's moss can be remolded at anytime.
- As shown in The Warlock Insane if witch's moss is ingested it can cause a state of temporary insanity with mass hallucinations and paranoia.