By Jeff Vlaming, who wrote "2Shy". Called "Earthling", which was the only episode of Fringe that actually dealt with aliens. It also includes a reference to "Leonard Betts". And there is even a "brain suck" in that episode, as Walter Bishop uses a vacuum cleaner to suck up the ashes of a victims head. So, literally, there was a "brain suck". But the "living shadow" angle is as far as the comparison goes... to ET or not ET?
This X-file is simply a "monster of the week", it has nothing to do with "Purity" or any other ET. An early version of this X-file has "Monks" shadow able to move independently- that would have been interesting to add that here, they added that capability into the Fringe "Shadow Man". In both shows the shadow basically had the same effect, Dead is dead. The effect in this X-file was amazing though. Little circles of ash with arms sticking out. This was only the second season and the state of the art of X-Files special effects had increased drastically from season one. And this was before digital effects.
We will recognize Skully's detective friend as the "woman" from "Gender-Bender", Kate Twa. She looks better, here. And she is just as imperious of a character as she was as a member of a crop circle creating cult that could be either sex at will... Which made her the best possible actress to use as the detective here. Skully is doing her a huge favor, which does not appear to be appreciated... Or reciprocated.
The character of Dr. Banton, played by Tony Shalhoub, is one of the most neurotic characters he has ever played and he has a reason not to trust anybody. Especially with "Mr. X" sniffing around, making matters worse.
Mulder and Skully can't really be of much help here as the entire case is being handled by cops who don't have a clue, and although they are giving good advice to Skully's friend, that advice is mostly ignored. To unfortunately fatal consequences. Even after Mulder figures out the "what" as it dawns upon him at the train station (to move the hell away from shadows), he is not in any position to protect Dr. Banton or those who would become, unwittingly, his victims.
And Mulder may even be responsible for piquing Mr. X's interest in Dr Monk, including everything that happens after the incident in the police station.
1/3rd of John Gillnitz wrote this, probably the first science fiction related script he had written and his very first X-file. It is not really an X-file as Mulder and Skully's involvement is peripheral throughout the entire debacle. Which is as frustrating for us as it is for Mulder and Skully. Because whenever a case is under their direct jurisdiction, they can at least do some good, even if it is minor. But they are shoved aside in this episode by the very people who asked for their help.
As it is, the Dramatis Personae involved in this incident have to fend for themselves, and carefully skirt the presence of Dr. Chester Ray Benton... if they can figure out why they should do so...
Otherwise, have you ever wondered what a dark matter dimension might be like? That is, if you could survive entry into it. Because there is one other thing about black holes that we know from reading any kind of science fiction: things that go in can never come out...