They are several specific types of mushroom which grow wild in damp fields and heaths around the UK between September and November. The most common type of Magic Mushroom is the psilocybe semilanceata one, and it is also known as 'liberty cap'. It is white and rocket shaped. Another is more potent and called amanita muscaria or 'fly agaric'. There are deadly poisonous species of amanitas and it is very hard to tell one type of mushroom from another (so if you are unsure absolutely don't take them!). The chemical in them, psilocybin or psylocin, works like a milder version of LSD. The Aztecs of ancient Mexico used to take some very strong magic mushrooms as part of their religion. They saw mystical visions, in between long bouts of severely throwing up.
One of the many chemicals in magic mushrooms, bufotenine, is also found in Chinese Toad skins