Star Trek: Deep Space Nine had “Far Beyond the Stars”, in which Sisko and the other main characters are all 1950s science fiction writers (framed as a hallucination Sisco is experiencing). IMO it’s a pretty good episode, but it is kind of weird in the context of the rest of the series.
I wonder if that’s where the creators of the Itchy & Scratchy Show got the idea to get Poochie off the show? 
The entire last season of DS9 had a holographic Vegas lounge singer, including an episode where the crew were forced to pull off a casino heist. Weirdly, apart from the heist episode it kind of worked.
It seems that every long-running fantasy/SF series eventually succumbs to the temptation of asking “What is real?”
ST:DS9 did the same thing, where Sisko was a frustrated and insane writer, and the whole series was a product of his fevered imagination.
“Once Upon a Time” also did that. Those are the only examples I can think of at the moment, but I’m sure there are plenty of others.
I just remembered an episode of “The Brady Bunch” which put the entire bunch in a ghost town’s jail.
I don’t remember that. If an execution was involved, I would have assumed that Briscoe and Green would be interviewing the executioner as a witness to some other crime, and rather than stop and talk to them he would just carry on executing the guy while answering their questions.
Legends of Tomorrow does this at least once a season. Offhand, there was:
- The time they got turned into puppets
- The one where they were trapped on TV
- When the Legion of Doom created Doomworld
For a true WTF Legends moment, it would have to be the time that the Legends realized their main villain Mallus sounded like actor John Noble [because he really was voiced by John Noble]. So they travel back in time to the set of The Lord of the Rings in New Zealand, and got John Noble (dressed up in full Denethor costume) to record a few lines so that they could trick one of Mallus’ (voiced by John Noble) minions. The episode was entitled “Guest Starring John Noble”.
The Simpsons episode where Skinner was an imposter. If you listen to the DVD commentary even the writer is having a hard time defending it.
This one is the one that led to the death of one of Jack’s assistants (she gave Brisco a ride home after he had been drinking, and got into an accident (leading to Jack’s later vendetta against a drunk driver)). Jack also goes to a cop bar and gets drunk.
“Smile Time” - Angel
Totally for the WTF? factor the writers intended.
All the talk about SF shows that did the “what is reality” stuff reminded me of an episode of Growing Pains where Ben wakes up to find out that his life is just a TV show. As expected, It’s All Just a Dream.
I seem to remember that plot showing up on other sitcoms, too. It could be a dream, or it could be some eerily similar in-universe TV show. I remember Boy Meets World did the latter. Family Guy does the version where the main characters’ lives actually inspire an in-universe TV show.
Though the latter show, being a cartoon, has too many weird shows for that to count as a WTF show. Such would have to be extremely outrageous, going beyond even the characters playing Star Wars.
I remember an episode during the final season of the 80s action series Riptide that was deliberately parodying Moonlighting, with fourth-wall breaking and characters resembling Maddie and David.
Another one from The Simpsons: “Brick Like Me,” a 2014 episode done almost entirely in LEGO animation.
I recall liking the capital punishment episode of L&O while thinking it was a really odd episode for the series.
This is hilarious, though!
Episodes of television shows (and other things) where someone discovers that their life was not real are not that uncommon. In the Twilight Zone episode A World of Difference (first shown on March 11, 1960), a man’s life turns out to be a just a television show, but then later it turns out to not be a television show. In the 1959 Philip K. Dick novel Time Out of Joint, a man’s life turns out to just be a constructed reality to keep him from knowing what’s really going on in his life. There’s the 1998 movie The Truman Show. There’s the Robert A. Heinlein short story “They” published in April of 1941 about a man discovering that the whole universe is a delusion constructed to fool him. There’s the 1999 movie The Matrix. There’s even a (not officially recognized) psychological condition called The Truman Show delusion in which people claim that their life isn’t real. Then there’s the message board called The Straight Dope in which . . . um, oh, never mind.
Every episode of Eerie, Indiana was WTF, but they did have one where Marshall finds he’s an actor in Eerie, Indiana.
Starsky & Hutch did a “vampire” story. John Saxon played the “vampire” (not an actual one, just a guy draining blood from women for a Satanic rite to resurrenct his dead wife…yeah, so that’s believable). Hutch, the more rational one of the pair, refuses to believe they are chasing a vampire, until there’s a rooftop chase and the guy (who’s fairly athletic) leaps from one roof to another. Hutch is stunned: “He flew!” Their regular informant Huggy Bear starts selling vampire kits (garlic, stakes, holy water). Hilarious episode.
I think Miami Vice did something similar, but with “aliens”.
I’m guessing that was the Halloween episode. Lots of shows ran weird stuff around then.
I can’t believe no one’s mentioned the clown rape episode of Little House on the Prairie yet.
Nikki and Paulo being buried alive in “Lost” certainly was not what I expected.