These episodes are why I watch the show. I remembered this one from youth as a solid episode but upon rewatch in adulthood, it is exactly what I liked of the show.
Tense, thrilling, a mystery to get lost in, this had it all. The only thing was a rushed ending with little to no explanation.
The episode seems to borrow from Shawshank Redemption in terms of the corrupt warden and death row setting. But in content, about a executed inmate vowing revenge on 5 who did him wrong, it is very different. People begin to die, some of the 5, some not. Lots of people are suspects, guards, inmates throwing into question whether this is a case of a supernatural revenge story or something concocted by the living (which is the usual X Files ambiguity of whether to believe or not to believe).
Everything in the plot feels purposeful. Most seem to like the x files comedy episodes like War of the Cocophages or Bad Blood (an episode I have always detested); both highly rated episodes, since they relax from the show's seriousness. Oh please! I watch the X Files for what it was intended to be not for it spoofing itself and its characters.
There's likely not one funny moment in this episode. But some great lines. "Warden, how does it feel to be on death row?" Love it love it love it.