In a hospital room in Madison, Wisconsin, Dave lay on a bed, looking at the trim around the ceiling. An air vent caught his eye. The sheen of metallic grate turned into pointed swords, and his mind filled with thoughts of Japanese martial arts and sword fighting. A few bright colors emerged, in contrast to the sanitized neutrals of the medical setting, and he heard notes of instrumental music. That’s all he remembers after receiving psilocybin, the active ingredient in magic mushrooms—though his trip lasted hours. (Dave requested a pseudonym because he worried that public knowledge of him taking psychedelics could hurt him professionally.)