Unruhe

Mulder and Scully investigate a series of abductions in which the perpetrator (Pruitt Taylor Vince) leaves behind photographs of his victims surrounded by spectral images.

Tropes:

• Anti-Villain: What Gerry does to his victims is truly nightmarish, but he's got a pretty big Freudian Excuse lurking in his past driving him to do it, and he believes that he's helping his victims overcome their "unrest."
• Distress Ball: Scully gets kidnapped.
• Eye Scream: Gerry Schnauz gives a transorbital lobotomy to troubled women, believing that it will help them. It used to be known as an icepick lobotomy and it involves inserting a leucotome through the eye sockets. Argh!
• Foreign Language Title: The title of the episode "Unruhe" is the German word for unrest, anxiety, unease, disquietude or restlessness.
• Gratuitous German: There are many German lines, courtesy of Gerry and Scully.
• Haunted Technology: Photography that can capture what's inside people's minds.
• Lobotomy: Gerry is a serial lobotomist. He thinks he's helping his victims and that he removes their inner demons. One girl is found dead and one is alive, apathetic and unable to speak.
• Never Recycle a Building: Gerry's father's dental office has been untouched since his death.
• Police Are Useless: One of the series' notable aversions, the local authorities play a major role in Mulder and Scully's investigation rather than obstructing or ridiculing it. Although it helps that they're facing a (mostly) normal killer whose supernatural powers don't help him much.
• Ripped from the Headlines: Of a sort. Vince Gilligan got the idea for the episode after reading an article about 1940s spree killer Howard Unruh, which noted that his name meant "unrest" in German. Gilligan found this tidbit weirdly poetic and contrived an episode around the idea. Although the similarities stop there: while Unruh was also diagnosed with schizophrenia, he shares neither motive nor method with Gerry and simply shot his victims rather than trying to "cure" them of unrest.
• Spooky Photographs: Of the foreboding type. They capture the victims' and Gerry's mind, leaving clues about their whereabouts. Played with a bit in that Mulder assumes that the shadows being cast in the photos are the shadow of the killer as he looms over his victims, dominating them — but it turns out it's because Gerry perceives his victims as being tormented by "the howlers," which in turn don't actually exist.
• What Kind of Lame Power Is Heart, Anyway?: Gerry has the most useless psychic superpower ever: unconsciously imprinting his schizophrenic delusions onto undeveloped film.