30 years ago, X-Files dropped the first clue as to who Mulder’s real father is

Hint: He’s a smoker

If you're ranking The X-Files seasons based on how many great episodes they contain, season 3 has got to be near the top of the list. (seasons 4 and 5 are also up there). Season 3, episode 2, “Paper Clip” cracks open a bunch of new avenues for the series mythology. A few episodes later, “Clyde Bruckman’s Final Repose” is a touching story about life and death. Vince Gilligan’s episode “Pusher” is an exciting thriller, while "Jose Chung's From Outer Space" is a downright hilarious spoof on alien abductions. But X-Files arguably saved its best reveal for last with the season 3 finale “Talitha Cumi,” which lays the first hint at one of the show’s biggest revelations.

Like all the season openers and closers of The X-Files, “Talitha Cumi” explores the show’s central mythology about the government conspiracy surrounding aliens and UFOs. The case that Agent Mulder (David Duchovny) and Agent Scully (Gillian Anderson) are investigating involves a mysterious man who healed people with the palm of his hand during a hostage situation at a fast food restaurant. Meanwhile, Mulder’s mother (Rebecca Toolan) has a stroke following a verbal confrontation with the mysterious Cigarette Smoking Man (William B. Davis).

Prior to this episode, we’d learned that the Cigarette Smoking Man had worked with Mulder’s dad, Bill Mulder (Peter Donat), at the State Department decades earlier and that Mulder’s father was formerly a part of “The syndicate,” the shadowy organization of which the Cigarette Smoking Man is a member. We’d also learned that, back in 1973, Bill Mulder had asked his wife to pick one of their children to be offered up as collateral to the alien colonists. She refused to choose, so Bill Mulder decided that Samantha, Mulder’s sister, would be abducted. Bill Mulder nearly told his son this in the finale of season 2, though before he got the chance, he was killed by the assassin Krycek (Nicholas Lea), on orders from the Cigarette Smoking Man. Mulder would later find this out from his mother.

In “Talitha Cumi,” the ties between the Mulders and the Cigarette Smoking Man are revealed to go even deeper. Before Mulder’s mom has the stroke, the Cigarette Smoking Man meets her at an old cabin by a lake where he and the Mulders used to vacation. He then alludes to an affair they had decades earlier.

It would be four seasons later, in season 7, episode 2, “The Sixth Extinction II: Amor Fati,” that the Cigarette Smoking Man would outright tell Mulder “I am your father.” Then in season 9, episode 19, “The Truth” — which was the series finale of the original run — the Cigarette Smoking Man’s confirmed son, Jeffrey Spender, outright says that Mulder is his half-brother as the result of the affair between the Cigarette Smoking Man and Mulder’s mother.

The fact that the character of the Cigarette Smoking Man became the central villain of The X-Files and the father to one of its two main characters is especially ironic when you consider that, as series director and producer Kim Manners once explained in a DVD interview, William B. Davis was hired to play “nothing more than an extra leaning against a file cabinet,” which is how he appeared, unspeaking, during Scully’s introduction in the pilot episode. Yet, something about his foreboding presence and the way he smoked those cigarettes turned him into “The Darth Vader of The X-Files,” as Manners described him.

Later on, when the series was revived for seasons 10 and 11 in 2016, the Cigarette Smoking Man would also be revealed as the father of Scully’s baby, as he had impregnated her with an alien/human hybrid back during season 7 of the original run. While some fans took issue with this revelation, it only added yet another layer to a character that was always full of surprises, with the seed of one of the biggest coming at the end of season 3 in “Talitha Cumi.”