Director: Jim Contner
Detective Kelly Ryan, one of Scully's ex-pupil at the academy asks for her assistance on her first ever case. Three people have vanished without a trace, the latest victim, Patrick Newirth disappeared from his locked hotel room leaving only a black smear on the floor near the door. Mulder toys with the idea of spontaneous human combustion. However when they discover that all three victims passed through the Richmond train station, Mulder and Scully review the station's security footage, a move rewarded when Mulder notices a man sitting at one spot in the station acting strangely.
On the video they can make out the badge he is wearing which leads them to a company called Polarity Magnetics. They show a photo of the man in the station to Dr Davey, who identifies him as his colleague Dr Ray Banton, who was researching dark matter. But Dr Banton has not been seen since he accidentally exposed himself to a massive amount of energy that burnt his shadow in to the wall. Mulder and Scully stake out the station and when Dr Banton appears, they attempt to arrest him.
Dr Banton warns them not to touch his shadow, Mulder realises that his shadow is deadly and arranges for him to be taken in to custody safely. However Detective Ryan and her department block Mulder and Scully from further access to Dr Banton. Frustrated Mulder contacts X about the case, but X tells him he can not help. Later X kidnaps Dr Banton and delivers him to a government laboratory to be tested on.
Scully here completely rebuffs Mulders suggestion of Spontaneous Human Combustion, but in the season 6 episode 'Trevor' she is the one to mention SHC, claiming that there have been "several well-documented cases". Perhaps she has had a change of opinion.
Actually in the show they say that Dr. Banton is composed of "dark matter" but then they mention "typical" known particles such as quarks, gluons, etc. which are all considered to our science as "normal" matter. If he really were composed of dark matter and it did have a devastating effect on normal matter, not only living beings would be affected, but everything.
Mulder: ... He believes the government is out to get him.
X: It's tax season. So do most Americans.