Whether they meant to do it or simply ingested it..
Ibogaine & its source plant, iboga, are powerful psychedelics with well-established anti-addictive effects — but it's not without its risk.
Amanita mushroom, AKA the fly agaric, is both hallucinogenic and poisonous. It's used in small doses to induce vivid and intense dreams. Amanita muscaria is legal in North America.
Mandrake is a real plant. It's toxic in higher doses and powerfully deliriant in lower doses. Learn about the strange world of the mandrake root.
Datura is a genus of hallucinogenic plants in the nightshade family. The hallucinations from this plant are often extreme & nightmarish.
N-Bombs (NBOMe) is a group of psychedelics often sold as LSD, but is much more dangerous.