X Files: Colony (s2 e16)
Summary: Unconscious and narrating, Mulder starts the episode in hypothermia and sure of extraterrestrial presence. A bunch of identical green-blooded guys being killed off by another green-blooded guy. Then, bam! The return of Samantha Mulder. Raised by one of the alien duplicates. Episode cliff-hangs with Scully staring at DoppelMülder.
Location: Beaufort Sea, Arctic Circle; Scranton, Pennsylvania; Binghamton, New York; Syracuse, New York; West Tisbury, Massachusetts; Tileston, Virginia
Guest Actors: Brian Thompson shows up in 9 episodes as the Alien Bounty Hunter.
David Duchovny gets a writing co-credit on this one.