Ketamine

Ketamine is a drug used in human and veterinary medicine developed by Parke-Davis (today a part of Pfizer) in 1962. Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist. At high, fully anesthetic level doses, ketamine has also been found to bind to opioid μ receptors and sigma receptors. Like other drugs of this class such as tiletamine and phencyclidine (PCP), it induces a state referred to as "dissociative anesthesia" and is used as a recreational drug.

Criminal Minds
Serial Killer Frank Breitkopf was known to have used ketamine to paralyze his victims before performing vivisection upon them. This would ensure that they remained alive and conscious during the procedure.