|| Randomly alters the form of a creature. It is especially effective against shape-changing creatures.
Polymorph is a monster-only spell which inflicts a temporary bad form transformation. Mutation resistance is useless against this, but magic resistance and worshiping Zin may protect you.
Prior to 0.14, players could find this spell in the Book of Transfigurations. It caused an effect similar to a wand of polymorph.
Prior to 0.12, this spell was called Polymorph Other. When used on the player by a monster, it had the same effects as Malmutate.