Psilocybin mushroom

Psilocybin mushroom, also known as "magic mushrooms" or just "shrooms", are a breed of mushroom plant that contains psilocin, which causes hallucinogenic effects on a person if they are consumed. In other words: If you eat one, then you'll be tripping balls.

On The X-Files, Fox Mulder took a psilocybin tablet in order to bring himself to an existential state of consciousness in the hopes of spiritually communing with a terrorist who had been in a coma. In addition to hearing the terrorist's message (in Arabic), Mulder also found himself wandering aimlessly through traffic and caused quite a stir when he began line-dancing at a country-western bar, terrifying several senior citizens.