Theef

"Theef" is the fourteenth episode of the seventh season of the science fiction television series The X-Files. It premiered on the Fox network in the United States on March 12, 2000. It was written by Vince Gilligan, John Shiban, and Frank Spotnitz and directed by Kim Manners. The episode is a Monster-of-the-Week" story, unconnected to the series' wider mythology. "Theef" earned a Nielsen household rating of 7.4, being watched by 11.91 million people in its initial broadcast. The episode received mixed to positive reviews from critics.

The show centers on FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) who work on cases linked to the paranormal, called X-Files. Mulder is a believer in the paranormal, while the skeptical Scully has been assigned to debunk his work. In this episode, Mulder and Scully investigate the murder of a prominent doctor's father-in-law, who was found with the word "theef" written on the wall in blood. After a string of follow-up accidents, Mulder suspects hexcraft may be the source of threats against the doctor's family.

"Theef" was written in a short period during the show's Christmas break after another script was dropped by the series. The main concept of the episode was "modern medicine versus backyards supernatural arts". The episode featured several noted actors, including Billy Drago, who played the role of antagonist Orell Peattie, and James Morrison, who was a former cast member of the science fiction series Space: Above and Beyond, which was created by former X-Files writers Glen Morgan and James Wong. Series creator Chris Carter later called the episode "very well cast".