Stand-alone episodes. Pretty much every TV show does them, even in this age of more serialized television. And oftentimes, they're kind of disposable. They're the cheap episodes, or the ones which don't shake up the show's status quo. Most of all, they're often stories that could come from any television show — like last week's "amnesia virus" episode of Terra Nova.
But stand-alone episodes don't have to be boring, and they don't have to be stories that any show could tell. Here are 10 stand-alone episodes that not only rock — they're also stories that could only have appeared on one show in particular.
10) The X-Files, "Clyde Bruckman's Final Repose"
Why it rocks: Peter Boyle guest stars as the titular psychic Clyde Bruckman who possesses the ability to see how people will die. Mulder and Scully use him to track a killer murdering psychics and tearing out their eyeballs in grand giallo fashion. This is a tightly written, suspenseful episode that balances dark humor with wanton violence (which would now seem tame.)
Why it could only come from this show: It's got a sort of quintessentially X-Files-ian blend of suspense and weirdness.
9) Futurama, "The Sting"
Why it rocks: It's a comedy sendup of Phiip K. Dick's Ubik with gigantic space bees centered on the death of the series lead. Fry's fate isn't revealed until the last eighty seconds of the episode, yet the hasty resolution makes perfect sense — It's the first and maybe only truly suspenseful episode of the series.
Why it could only come from this show: It's hard to imagine any other show pulling off something quite so insane and so steeped in science fiction references. The off-the-wall humor is pure Futurama.
8) Andromeda, "Belly of the Beast"
Why it rocks: This is a fan-favorite episode, in which the Andromeda is swallowed by a huge space creature called the Cetus, which is sort of a huge jellyfish. Dylan and Trance are off the ship at the time, ironically because they're the only ones who take the threat of the Cetus seriously, and thus the crew is left to deal with the situation on their own. In the end, Dylan realizes that his crew have learned from his own death-defying example.
Why it could only come from this show: It's really all about the relationship between Dylan and his crew, and how he's influenced them with his indomitable swashbuckling ways. It's hard to imagine this being about anybody but Kevin Sorbo.
7) Batman: The Animated Series, "Baby Doll"
Why it rocks: This is a divisive episode, to say the least — it involves a former child actress, Marion Dahl, who's suffering from a fictitious medical condition called "systemic hypoplasia," which keeps her in the body of a small child even as her mind matures into adulthood. This puts a damper on her attempts to become a successful dramatic actress. So what does the permanently child-bodied Dahl do? Kidnap her former costars, of course.
Why it could only come from this show: Batman: TAS did a lot to elevate the Caped Crusader's science fiction adversaries to become key players, but the show also wasn't afraid to create new enemies and take weird risks, making for a tone that few animated shows before or since could match. And Paul Dini's warped fingerprints are all over this cartoony, twisted episode.
6) Farscape, "Crackers Don't Matter"
Why it rocks: The first truly unhinged episode of Farscape, this story was a last-minute replacement for another script that didn't work out. On the surface, it's your typical "crew goes insane and turns on each other" story, but the actual storytelling goes way further and is more nuts. The episode does introduce Crichton's imaginary version of Scorpius, Harvey, but Harvey was intended as a one-off at the time.
Why it could only come from this show: Mostly because the insanity that unfolds is quintessentially Farscape, including the famous scene where D'Argo force-feeds the puppet Rygel.
5) Fringe, "White Tulip"
Why it rocks: I have to admit, I was lukewarm about this episode when it first aired, but I've come to appreciate it a lot more. Genre MVP Peter Weller plays a scientist who develops a method of time travel that has a few lethal drawbacks — and the body count piles up while Weller seeks a way to repair the timeline and save his true love. The interplay between Weller's character and archetypal mad scientist Walter Bishop is what makes it great.
Why it could only come from this show: Even though it's a "freak of the week" type episode, the two mad scientists make a special connection, and Walter Bishop's tormented sense of whimsy is integral to the story. Unlike a lot of one-off Fringe episodes, you couldn't just plunk down a different team of investigators and have it work.
4) Doctor Who, "Blink"
Why it rocks: One of the times we interviewed Neil Gaiman, he cited this story (along with "City of Death") as Doctor Who stories that you could show to a new viewer instead of trying to explain the show to them. True, it introduces the Weeping Angels, which are later seen again, but I have a feeling they were intended as one-off villains. It also introduces a great one-off character, Sally Sparrow, and tells a brilliant self-contained story in which the pieces all end up fitting.
Why it could only come from this show: Few shows could have pulled off such a time-travel-intensive story, plus the TARDIS is vital to the story's resolution. And it wouldn't really work quite as well without David Tennant's brief but memorable appearances.