David Duchovny FBI Special Agent Fox Mulder Actor Gillian Anderson FBI Special Agent Dana Scully Actor Mitch Pileggi Asst. Dir. Walter Skinner Guest Star Nicholas Lea Alex Krycek Guest Star Brian Thompson Alien Bounty Hunter Guest Star William B. Davis Smoking Man Guest Star Steven Williams Mr. X Guest Star Bonnie Hay Field Doctor Guest Star Bruce Harwood John Fitzgerald Byers Guest Star Sheila Larken Margaret Scully Guest Star Andrew Johnston Agent Barry Weiss Guest Star Dean Haglund Richard "Ringo" Langly Guest Star Tom Braidwood Melvin Frohike Guest Star Hrothgar Mathews Man on Phone Guest Star Megan Leitch Samantha Mulder Guest Star Michael David Simms FBI Agent Guest Star Peter Donat William Mulder Guest Star Dwight McFee Commander Guest Star Kathleen Duborg Mother Guest Star Oliver Becker 2nd Doctor Guest Star Chris Carter Writer, Executive Producer, Director Glen Morgan Writer Howard Gordon Writer Paul Brown Writer Frank Spotnitz Writer Sara B. Charno Writer Darin Morgan Writer Rob Bowman Director James Wong Writer James Whitmore Jr. Director Win Phelps Director Stephen Surjik Director Alex Gansa Writer Vince Gilligan Writer David Nutter Director R.W. Goodwin Director Kim Manners Director James A. Contner Director