Psilocybin mushrooms, commonly known as magic mushrooms or shrooms, are a polyphyletic informal group of fungi that contain psilocybin, which turns into psilocin upon ingestion. Biological genera containing psilocybin mushrooms include Psilocybe, Panaeolus, Inocybe, Pluteus, Gymnopilus, and Pholiotina.

A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. Toadstool generally denotes one poisonous to humans.