The X-Files - Season 8 - Eps 20: Essence (1)
Mulder and Doggett join forces to investigate the arson attack on a genetics lab where one of the doctors suspected of experimenting with alien impregnation is killed. They encounter Billy Miles, who has been changed into an alien replicant after his recent abduction and is attempting to erase evidence of the tests. When a woman helping Scully out at home is found to be a part of the conspiracy, the agents, along with Monica Reyes and Alex Krycek, know they must protect Scully and her baby from Billy Miles and get her out of the city.
About The X-Files

Title: The X-Files
First Air Date: 1993-09-10
Last Air Date: 2018-03-21
Status: Ended
Rating: 8.4/10 (from 3182 votes)
Language: EN
Seasons: 12
Total Episodes: 218
Network: FOX
Genres: Mystery, Sci-Fi & Fantasy, Crime
Production Companies: Ten Thirteen Productions, 20th Century Fox Television
Synopsis
The exploits of FBI Special Agents Fox Mulder and Dana Scully who investigate X-Files: marginalized, unsolved cases involving paranormal phenomena. Mulder believes in the existence of aliens and the paranormal while Scully, a skeptic, is assigned to make scientific analyses of Mulder's discoveries that debunk Mulder's work and thus return him to mainstream cases.
Cast

David Duchovny
Fox Mulder

Gillian Anderson
Dana Scully

Mitch Pileggi
Walter Skinner