Mushrooms are a Halosagenic (Don't know if i've spelt it right) They make you see things that aint there, Crazy drug, ive heard stories that put me off ever trying one
(Hallucinogenic, it was bugging me.)
Mushrooms as a whole are not hallucinogenic, most are just fairly common fungi growing in a nutrient rich areas breaking down all available nutrients via a mycelium network. Mycelium is made up of hyphae, and is the core of the fungus. As the mycelium spreads through soils, or tissues, the fungus will grow a mushroom. This is the fruit of the fungus designed to produce spores, that will grow into a new mycelium network elsewhere. Mushrooms have individual ways of dispersing their spores, these can be shown with spore patterns. There are however some extremely toxic mushrooms, this is because of metabolic reactions occurring in the mycelium pathways.
Take care not to randomly eat mushrooms found in the forest, or various other places, unless of course you were bored enough that you were okay with being dragged to a conference about mushrooms and know how to identify them.
(I was reeeeeealllly bored.)