Darin Morgan had a small involvement in the second season, and was asked to contribute more content for the third. He first appeared in "The Host" as the Flukeman, and was brought on by his brother Glen Morgan to help write the episode "Blood". Morgan's first sole credit as a writer came in the episode "Humbug", which received a positive reception by the staff. David Duchovny expressed an enjoyment for working with Morgan, commenting "what I loved about his scripts was that he seemed to be trying to destroy the show." Morgan wrote a total of three episodes, but later left the series because he could not keep up with the fast-paced nature of network television. He also expressed a negative opinion of the way his teleplays were handled, despite a positive reception by both critics and the crew of his work. He also contributed to the script for the episode "Quagmire". After writing one episode the previous season, Vince Gilligan returned to write another solo episode for the season, now credited as a creative consultant. Cast member David Duchovny collaborated with Howard Gordon and Chris Carter for two episodes receiving story credit.