 Chad Donella was cast as the lead monster because he possessed a "subtle, interesting quality," according to casting director Rick Millikan. Director Kim Manners latter described Donella as a "great little actor." Duchovny's stunt double, Steve Kiziak played the role of the private detective — also called Steve Kiziak — that Roberts kills and eats. Kiziak later said, "It was a lot of fun to be in front of the camera." Kiziak had first appeared as Duchovny's body double in the third season episode "2Shy," and would later appear as a Mulder lookalike in "Fight Club."
