h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Amanita muscaria is edible.

Not in the sense of the mushrooms you buy in the supermarket. Amantia Muscara and Amantia Pantherina are both halucinagenic mushrooms, and can kill in high doses (although that would take something in the range of 10-30 mushrooms, but irreperable damage may occur with a considerably lower dose). Unlike other halucinagenic mushrooms, such as the Psilocybe Semilanceata (liberty cap) and Hyphaloma Cyanescens, Muscara and Pantherina are extreemly variable in the percentage of halucinagens present in them (owing to growing conditions, soil fertility, temperature, humidity etc), and can vary from just 0.1 mg of halucinagens per gram of dry mass to a whopping 1.2 mg, so great care must be taken when using a new batch of these mushrooms. When testing these Amantias, start by taking 3 quarters of a gram of dried mushroom on the first test, waiting 4 days (since you build up a resistance to these drugs extreemly quickly), testing again with 1.5 grams, waiting another 4 days and testing once more with 3 grams. This should give you a fairly good idea of the effective doses of that particular batch of Amantia.

Wasn't this the Marquis de Sade's downfall? He'd got it into his head that amanita muscaria was an aphrodisiac, and fed it to a couple of ladies of negotiable affection whom he'd hired for the day... on a tip-off, the police raided to find two very badly poisoned prostitutes suffering all the described symptoms, and busted de Sade for administering a lethal substance.