Few drugs are as two-faced as ketamine. By day, it works as a legitimate anesthetic, sitting comfortably on the World Health Organization’s list of Essential Medicines. By night, though, it moonlights as a party drug, sending users into an intense dissociative state (read: not in touch with reality) known as a K-hole. Of late, ketamine has also been finding work as a novel antidepressant, administered intravenously in not-illegal-but-also-not-mainstream clinics.