"The Springfield Files" is the tenth episode of the eighth season of the American animated television series The Simpsons. It originally aired on the Fox network in the United States on January 12, 1997. In the episode, Homer believes he has discovered an alien in Springfield. It was written by Reid Harrison and directed by Steven Dean Moore. Leonard Nimoy guest stars as himself and David Duchovny and Gillian Anderson guest star as agents Fox Mulder and Dana Scully, their respective characters on The X-Files. The episode serves as a crossover with The X-Files and features numerous references to the series. The story came from former showrunners Al Jean and Mike Reiss, who returned to produce this episode while under contract with The Walt Disney Company. It received positive reviews from critics; Jean and Reiss won an Annie Award for producing it.

Fox William Mulder is a fictional FBI Special Agent and the secondary protagonist of the Fox science fiction-supernatural television series The X-Files, played by David Duchovny. Mulder's peers dismiss his many theories on extraterrestrial or paranormal activity as those of a conspiracy theorist and supernaturalist; however, his skeptical but supportive partner, Special Agent Dana Scully, often finds them to be unexpectedly correct. He and Scully work in the X-Files office, concerned with unsolved FBI cases that are often revealed to be supernatural or extraterrestrial in nature. Mulder was a main character for the first seven seasons, but was limited to a recurring character for the following two seasons. He returns as a main character for the tenth and eleventh seasons.