alien bounty hunter?" Carter was positive towards the idea and acted upon it, creating with Spotnitz the character of the Alien Bounty Hunter for the two-part episodes "Colony" and "End Game". Actor Brian Thompson auditioned for the role in a casting session, where he was competing with another actor. Spotnitz and Carter did not have much time to cast the character, but they knew this casting would be important since they intended the character to become a recurring character. Thompson was chosen according to Spotnitz because he had a very "distinctive look" about him, most notably his face and mouth. Megan Leitch also appeared in "Colony" and "End Game" as a grown-up clone version of Samantha Mulder, and would return to play Samantha or one of her clones over the other seasons. Carter did not want it to be the real Samantha, since that would have been "straight science fiction" and it was too "ridiculous" to give too many answers. Darren McGavin, star of Kolchak: The Night Stalker, was sought out for the part of Senator Matheson in "Little Green Men" and Mulder's father in "Colony" and "End Game", but the roles went to Raymond J. Barry and Peter Donat respectively, while McGavin agreed to play X-Files founder Arthur Dales in season five. Crew Carter also served as executive producer and showrunner and wrote seven episodes. Co-executive producers and writing team Glen Morgan and James Wong wrote five episodes for their final season as regular writers for the series, although they would both return as consulting producers for part of season four. Supervising producer Howard Gordon wrote five episodes. Frank Spotnitz joined the series, writing two episodes. Cast member David Duchovny collaborated with Carter for two episodes receiving story credit. Glen Morgan's younger brother Darin Morgan joined the series, contributing the story for an episode written by his older brother and James Wong, and writing another script solo. Paul Brown joined the series as a producer and wrote two episodes. Sara B. Charno, another staff writer, wrote two episodes. Vince Gilligan joined the series, writing one episode. Former supervising producer Alex Gansa returned to co-wrote one episode with writing partner Howard Gordon. Chris Ruppenthal returned to write one more freelance episode after last season. Steve De Jarnatt also contributed one freelance episode for the season. Line producer and production manager Joseph Patrick Finn was promoted to producer with this season.