癌人
The Smoking Man is the only character in the series, in addition to Mulder and Scully, to appear in both the first episode, "Pilot" and the last, "The Truth" of the series. Portraying actor William B. Davis was listed as CIA Agent in the first season episode "Young at Heart", instead of his usual character, the Smoking Man. Actor Chris Owens for a time portrayed the Smoking Man as a young man in flashbacks. He later plays his son, Jeffrey Spender. Young Cigarette Smoking Man was first played by Craig Warkentin, with Davis' voice dubbed over in "Apocrypha".