The appearance of Samantha Mulder, this time as a clone of her from when she was still a little girl, was due to series creator Chris Carter's desire to bring her back. Carter felt Samantha was an important element of the show, referring to her as being part of the lifeblood of the series. The decision to kill the character X was made at the end of the third season. The writers felt that they could only do so much with the character and decided that they would either make him a bigger player on the show, or have him pay the price for collaborating with Fox Mulder. Ultimately they decided on the latter. This led to the introduction of Marita Covarrubias at the end of the episode, Mulder's latest informant.