X-Files, Season 5, Episode 12: “Bad Blood.”
While investigating a series of bizarre exsanguinations in the sleepy town of Chaney, Texas, about 50 miles south of Dallas, Mulder kills a teenage boy wearing fake vampire fangs, whom he “mistakes” for a vampire by pounding a stake through the boy’s heart.
The young man’s family is now suing the FBI for $446 million, and Mulder and Scully are brought before FBI Director Walter Skinner to tell their versions of what happened. Prior to making their reports, Mulder and Scully attempt to get their stories “straight” by relating to each other their differing versions of what happened during their investigation.
(combination of the wiki and the imdb)
Sheriff Hartwell: You really know your stuff, Dana.
(Dreamy music. Scully smiles goofily and the scene shifts back to real time)
Mulder: Pffft! Wh–? “Dana?!”
Mulder: He didn’t even know your first name.
Scully: (pause) … You gonna interrupt me or what?
Mulder: Oh, no-no. You go ahead … Dana.
Scully: Mulder, are you okay?
Mulder: [drugged] “Who’s the black private dick who’s a sex machine with all the chicks? Shaft! Can you dig it? They say this cat Shaft is a bad mother —
Mulder: (singing) — shut yo’ mouth! I’m jus’talkin’’bout Shaft!”
(Scene shifts back to real time)
Mulder: I did not.
Guest stars were Luke Wilson (Home Fries, Legally Blonde, The Royal Tenenbaums, Old School, bloated phone commercials that remind me that age comes inevitably for us all, and that ripening is not always kind even to handsome Hollywood guys you once wanted to boff that you thought would stay hot forever) as Sheriff Lucius Hartwell and Patrick Renna (“Ham” in The Sandlot!) as Ronnie Strickland.
Mulder: It’s all true.
Scully: Except for the part about the buck teeth.
(repeated line): I was drugged.
Gillian Anderson voted this her favorite episode of all time.