Warning: major spoilers ahead for Episode 6 of The X-Files Season 11, called "Kitten."
Walter Skinner (Mitch Pileggi) has been a key character on The X-Files from almost the very beginning. His loyalties have shifted a few times over the series -- for reasons ranging from a bad guy infecting him with a nanovirus to Skinner himself making a deal with the Cigarette-Smoking Man to save Scully -- but fans haven't gotten a real origin story for the character. Fortunately, Season 11 finally delivered the kind of Skinner-centric episode (including flashbacks!) that we've been waiting for, and it was absolutely heartbreaking.
In "Kitten," Skinner went AWOL from the FBI and journeyed to a remote area in Kentucky, charmingly called "Mud Lick," after receiving a message (and severed ear) from one of his former Vietnam comrades-in-arms, John "Kitten" James (Haley Joel Osment). As it turns out, Kitten was a soldier who had been drafted into the Vietnam war around the same time that Skinner eagerly joined up to serve his country. Their unit was tasked with protecting a mysterious crate, which turned out to be filled with a weaponized experimental gas that forced those affected to see horrific visions of a monster. Skinner only breathed a small amount of the gas after the crate was shot, but Kitten was surrounded in it, and it more or less broke his mind, driving him to kill a lot of people.
Young Skinner was pressured by the military to lie about what had happened and omit any mention of the gas from his testimony in Kitten's case, and Kitten was sent to a mental hospital for more than 30 years. Although Skinner wasn't at fault for Kitten's exposure to the gas, he has been haunted by what happened to Kitten ever since Vietnam. When he got the message (and ear) from John, he hastened to Mud Lick to try and help any way he could. Unfortunately, John hanged himself before Skinner arrived, leaving his son Davey (also Haley Joel Osment) alive and looking for vengeance.
Blaming Skinner for falsely testifying in his dad's court martial, Davey led the Skinman into the woods, showed him Kitten's body hanging from a tree, and then tricked Skinner into falling into a booby-trapped pit filled with stakes. Even worse, he cut his father's body down from the tree so that it fell right on top of Skinner. Poor Skinner was skewered by a stake, stuck in a pit, and sharing a small space with the corpse of his former friend. Suffice it to say that "Kitten" isn't the most hilarious episode The X-Files has ever produced.
The good news is that Mulder and Scully were on the case. Mulder discovered Skinner in the pit, then promptly fell down the pit himself. Luckily, Scully was smart enough not to immediately fall down into the pit, and she was able to shoot Davey before he could drench Mulder and Skinner in gasoline and light them on fire. She only wounded him, however, and he escaped to run away. He led Mulder and Scully on a merry chase that almost resulted in their deaths by booby trap, but the injured Skinner showed up in time to knock Davey under the trap instead, killing his former friend's son via lots and lots of stakes.
If that's not heartbreaking enough, Skinner spent the episode dealing with his Vietnam demons, not the least of which was how he was forced to shoot a 10-year-old Vietnamese boy in the head when he walked up to Skinner's unit wearing a bunch of grenades, earning the nickname "Babykiller" from his comrades. "Kitten" also revealed that the reason Skinner has been "Assistant Director" Skinner for the past 25+ years is that he supported Mulder and Scully in their attempts to chase aliens and monsters with badges and guns. He told the agents that he was proud to have supported them and that they saved his life more than once. The events of "Kitten" were traumatizing enough that he feels compelled to do what he can to expose the government's previous and ongoing experimentations with gases, career be damned if that's what it takes.
Sadly, the Skinman's time may be limited. "Kitten" revealed that exposure to the gas results in teeth falling out, and Kitten's teeth were already falling out when they were still in Vietnam. The episode ended with Skinner pulling a bloody tooth out of his mouth. He may begin seeing monsters just as Kitten had. Will Skinner's suffering never end?
Before "Kitten," we knew bits and pieces of Skinner's past in Vietnam. He'd previously shared the story of shooting the young boy, and he'd confessed to what was either a hallucination or a haunting paranormal experience. It was also a pretty safe bet that Skinner had been held back at the FBI due to his support for the X-Files unit. "Kitten" showed via flashback what we'd been told, and it gave a deeper glimpse into what makes Skinner tick after all these years. We now know more about why Skinner is the way he is, which makes "Kitten" an incredibly rewarding episode for longtime fans who have been watching him for a couple of decades at this point.
The good news for Skinner is that this experience seemingly resulted in Mulder and Scully coming to trust him again despite their suspicions of a renewed connection to the Cigarette-Smoking Man. Given that those suspicions aren't exactly unfounded, it should be interesting to see how they react if/when they discover why he's been working with Old Smokey again.