Sporicin

A drug (hallucinogenic? narcotic?) derived from poisonous black mushrooms and a magical Bes spring in the basement of the Forceful Spider tavern, hideout of the Scorpion Bandits. Gessel the Apothecary was the prisoner who refined the black fluid form. Presumably all was destroyed by Varis after the bandits were defeated. Known users included Hakama and Mayor Ales.