S4E6 · Sanguinarium

During a routine liposuction operation in Winnetka, Illinois, Dr. Harrison Lloyd (John Juliani) suddenly begins to remove so much fat that his patient dies. Lloyd later tells Fox Mulder (David Duchovny) that he killed the patient because he was possessed; Dana Scully (Gillian Anderson) is skeptical, believing he is only making it up to escape legal consequences.

Mulder inspects the operation room and discovers a pentagram burned into the floor; he begins to suspect that witchcraft might have played a part in the crime. Meanwhile, staff at the clinic are shocked when another plastic surgeon, Dr. Ilaqua (Paul Raskin), kills an elderly patient by burning a hole through her cheek and neck with a surgical laser, severing her brain stem. Scully interviews Ilaqua, who claims that he cannot remember anything of the incident. Mulder's suspicions are strengthened when he reviews the tape of the second murder and sees a pentagram-like pattern on the stomach of the victim.

Worried by the events, the clinic's coordinator, Dr. Theresa Shannon, tells Mulder and Scully about a similar series of deaths that occurred there ten years prior. They suspect Rebecca Waite (O-Lan Jones), a nurse who is the only person present at all the death scenes. The agents visit Rebecca's house, discovering evidence that she practices witchcraft; however, the evidence was planted there by a staff member of the hospital. Elsewhere, Dr. Jack Franklin (Richard Beymer) is non-fatally assaulted by Rebecca at his house. There, Rebecca is arrested by the agents, who attempt to question her but are prevented when she starts to vomit pins, dying shortly thereafter.

After the incident, Mulder visits Franklin, hoping to learn more about Rebecca's possible motivation. Although Franklin is seemingly innocent, when Mulder leaves the room, he begins to levitate and devilishly smile. Later that night, Mulder deduces that the birthdays of all the victims match up with the dates of the Witches' Sabbath and that Rebecca was actually trying to protect the victims from Franklin, using the pentagrams as protective symbols. Unfortunately, Mulder also realizes that because Rebecca was not the murderer, the spree of murders will continue. As he's suspected, another patient is murdered with acid at the clinic.

Soon after, the agents again meet with Shannon, who divulges that five people died during the previous killing spree: four patients and a cosmetic doctor named Clifford Cox, who ostensibly died of a drug overdose. Although his birthday does not align with a Sabbath date, Mulder instinctively believes that Cox is involved in the crimes. He uses the clinic's computer program to determine what Cox would look like had he undergone heavy plastic surgery. The computer produces an image that looks like Franklin, suggesting that he is actually Cox in disguise.

When Shannon discovers Franklin alone in a blood-spattered operating room, he uses witchcraft to magically teleport surgical tools into her intestines, which causes her to bleed internally. She is rushed into surgery and survives. Meanwhile, Franklin removes the skin of his face, performs a ritual to make him appear younger and escapes while a patient (listed with a birthdate of October 31) nearby is found with their face gone. It is implied that he murders in a quest to gain eternal youth. The episode ends with a now-younger Franklin successfully applying for a position at another hospital.