History Main / AlternateRealityEpisode

* Creator/DCComics pretty much specialized in this form of storytelling, publishing ''dozens'' of stories from the 1950s onwards where, either as a one-off "change of pace" storyline or as a back-up story "filler" (common in the days when some issues ran for 80-100 pages ''without ads'' in some cases, and needed to be filled). In the 1980s, DC launched its "Elseworlds" line, with followed the same concept, except usually with more serious stories.

Typically, the "normal" situation may get a look-in for a couple of scenes at the start or end of the episode, but there should not be any clear link between the characters - Alice the millionaire should not wake up as Alice the research assistant, or have Bob her millionare buddy visiting her, asking why everything is different.

* ''Anime/NeonGenesisEvangelion'' [[Recap/NeonGenesisEvangelionEpisode26TakeCareOfYourself Episode 26]] has what is more of a Alternate Reality Segment, but it plays out like such an episode none-the-less, showing a world where the series, instead of being a ScienceFiction {{Mecha}} Drama set AfterTheEnd, is a SliceOfLife RomanticComedy set in a perfectly normal (well, normal by anime standards) HighSchool. The segment plays out in-universe as an attempt to show Shinji that he could lead a happy life without being an Evangelion pilot.
* In an anime only episode of ''Manga/RanmaOneHalf'' Ranma and Akane are discussing how Genma is away training for way too long. Meanwhile Genma fell off a cliff and into a river. Then in his panda form he's found by who he believes to be Ranma, Akane and Kuno. However they don't recognize him and call themselves Kotaro, Kanna and Hayato. Soon he's welcome as a prophesized lucky panda to the feudal-esque town where almost the entire main cast except himself exists, with similar relationships. He helps Kotaro and Kanna defeat Hayato and makes them hold hands, prompting the family and villagers to cheer them into marriage. He's then accidently knocked off another cliff and he returns home and makes the real couple hold hands too. No explanation is ever given about this alternate reality.

* "The Unwritten Fables", the final arc of ''ComicBook/TheUnwritten'' vol. 1, crosses over with ''ComicBook/{{Fables}}'' in an alternate reality where [[spoiler:BigBad Mr. Dark was never defeated and the remaining Fables are constantly on the run]].

** "Parallel Lives" has the crew interact with a [[GenderFlip gender-swapped]] version of themselves, led by a woman named Jane Tiberia Kirk.
** "Connection" is a two-part story in which the crew from both timelines start experiencing each other's timelines, including the probes they sent switching places.

* The ''Franchise/{{Superman}}'' story arc ''ComicBook/TheDominusEffect'' is one where Superman himself is cast into four different realities as four different versions of himself, three of which are based on [[UsefulNotes/TheGoldenAgeOfComicBooks the Golden Age]], [[UsefulNotes/TheSilverAgeOfComicBooks the Silver Age]], and [[UsefulNotes/TheBronzeAgeOfComicBooks the Bronze Age]], and the fourth being a future age which is based on a Silver Age imaginary storyline.
* ''ComicBook/TheTransformersMarvel'' has “Instruments of Darkness”, set in a BadFuture where Unicron devoured Cybertron and Galvatron now rules over a decimated Earth. Though it avoids being total filler when [[spoiler: The main universe’s Unicron has his minions teleport Galvatron to serve him at the end of the issue]].

* In the two-part ''Series/ThirdRockFromTheSun'' episode "Dick'll Take Manhattan", the aliens go through a time-space portal to a parallel universe where they lead upscale lives in New York City. Dick is a lawyer, Sally is a columnist in the vein of ''Series/SexAndTheCity'', Tommy is a cast member on ''Series/SaturdayNightLive'' (with then cast members Tracy Morgan, Ana Gasteyer, and Darrell Hammond appearing as themselves), and Harry is the president of Creator/{{NBC}}. Other characters from the show turn up as well, all leading different lives of some description. Inevitably, the Solomons return home after finding their new lives to be shallow.
* A variation with the first season 8 episode of ''Series/{{Arrow}}'', which appears to start as a variation on the show's pilot, with Oliver returning home from Lian Yu... but 12 years after disappearing instead of 5. He learns that his mother married Malcolm Merlyn and that Thea died of a Vertigo overdose. We eventually learn that he's actually on Earth-2, as Laurel immediately recognizes him. In addition, Adrian Chase is this world's Hood (unknown what happened to Robert Queen, since he was mentioned to be the vigilante of that name), while [[spoiler:Tommy Merlyn is the Dark Archer, seeking to punish the Glades for his sister's death with his own version of the Undertaking]]. Also a zigzag with Oliver being introduced to his bodyguard John Diggle in the same manner as in the pilot... except this is Dig from Earth-1, having followed Oliver using Cisco's interdimensional extrapolator. [[spoiler:Oliver manages to stop the Undertaking and obtain the dwarf star particles the Monitor needs, only to witness Earth-2 being wiped out by an antimatter wave, barely escaping in time with Dig and Laurel.]]

* ''Series/BuffyTheVampireSlayer'':
** Played ''terrifyingly'' in "[[Recap/BuffyTheVampireSlayerS3E9TheWish The Wish]]". Cordelia, bitter over her failed relationship with Xander, makes an idle wish that Buffy had never come to Sunnydale, believing that her [[AlphaBitch popular status]] would still be intact if she had never gotten involved in the Scoobies' affairs; unfortunately, she speaks in front of a disguised vengeance demon who [[BeCarefulWhatYouWishFor grants her wish to the letter]]. Cordelia is tossed into a [[CrapsackWorld crapsack]] alternate timeline where the Sunnydale population is a tenth of what it was, due to unchecked vampire attacks, due in turn to the Master having ascended a year and a half before without Buffy there to stop him. Cordelia is killed by evil vampires Willow and Xander, Giles and Oz are trapped in thankless work as desperately outnumbered vigilantes attempting to do what they can to restore some semblance of safety to the community, Angel is kept in a cage with the Master's minions allowed to torture him for fun, and Buffy eventually makes an appearance as a hardened, pitiless rogue Slayer who has gone off the deep end without her friends' humanizing influence. The episode ends with a vicious FinalBattle in which the entire main cast kills each other; Giles' last-minute actions save the day and propel everyone back into their proper reality, but it's still incredibly frightening.
** "[[Recap/BuffyTheVampireSlayerS3E16Doppelgangland Dopplegangland]]" was a play on this trope. Vampire!Willow from the alternate reality of The Wish accidentally finds her way to the real world, setting some serious {{foreshadowing}} for further seasons.
** Played with in "[[Recap/BuffyTheVampireSlayerS6E8TabulaRasa Tabula Rasa]]", where Willow casts a spell intended to remove Tara's memory of breaking up with her but instead blanks out everyone's memories including her own. They're in the same reality but because they're all starting from a blank slate they reach some very different conclusions about themselves. Giles and Anya think they're engaged, Spike thinks he's a vampire with a soul (usually Angel's role) and Buffy finds being a Slayer cool.
** "[[Recap/BuffyTheVampireSlayerS6E17NormalAgain Normal Again]]" had Buffy, under the effects of a demon's venom, flashing between the normal Buffyverse, and an alternate reality where she had spent the last six years catatonic in a psychiatric hospital in Los Angeles, where they have been trying to treat her for insane delusions about fighting vampires and demons. [[AmbiguousSituation The episode makes no attempt whatsoever to definitively confirm which, if either, of Buffy's perceived realities are the real thing.]]
** The spin off ''Series/{{Angel}}'' had "[[Recap/AngelS03E11Birthday Birthday]]", where Cordelia got a chance to make her life what it would have (or ''should'' have according to the one offering her the choice) been like [[ForWantOfANail if she had met a big-time talent agent instead of running into Angel in the pilot]]. She becomes famous but Angel gets the visions (because Doyle still died) and it drives him mad. Wes and Gunn are with him, but with only three arms between the two of them.

* ''Series/DoctorWho'':
** In [[Recap/DoctorWhoS7E4Inferno "Inferno"]], the Doctor winds up in an AlternateUniverse where it's implied that he was never there to help Earth out when it needed him. Britain has become a fascist dictatorship, his usual allies are no-nonsense jackboots who've never met him and thus are much harder to persuade, and the drilling project that threatens Earth in the main timeline has already progressed to the point of irreversibility, resulting in Earth's destruction. The Expanded Universe would indicate that in this universe, the Doctor became the dictator himself, thus making him humanity's oppressor rather than its savior. The Doctor eventually manages to get back to his own universe and stop the drilling there in time, but is left traumatized by the events that transpired in the other universe.
** In [[Recap/DoctorWhoS30E11TurnLeft "Turn Left"]], an alternate universe is created around Donna Noble where she never met the Doctor, and as a result, [[Recap/DoctorWho2006CSTheRunawayBride he died that Christmas stopping the Racnoss Empress]], which led to Donna losing her job, although she did win a trip out of town for the next Christmas. Good thing, too, because without the Doctor there to help, [[Recap/DoctorWho2007CSVoyageOfTheDamned London was nuked]], everyone in the city died, and Britain became an ethnonationalist dictatorship. Because he wasn't there, [[Recap/DoctorWhoS29E1SmithAndJones almost everyone in the Royal Hope Hospital suffocated when it was transported to the Moon]], including Martha Jones — who never met the Doctor in this timeline — and [[Series/TheSarahJaneAdventures Sarah Jane and her friends]], who stopped the sabotaged MRI from going off. It goes FromBadToWorse: The Doctor and Donna weren't there to [[Recap/DoctorWhoS30E1PartnersInCrime stop the Adipose]], and tens of millions of Americans were killed. [[Recap/DoctorWhoS30E4TheSontaranStratagem The Sontarans nearly succeeded]] [[Recap/DoctorWhoS30E5ThePoisonSky in rendering the planet inhospitable]], saved only by the heroic sacrifices of the Series/{{Torchwood}} team. And ''then'' [[TheStarsAreGoingOut the stars go out.]]
* ''Series/TheFlash2014'' starts its third season with Flashpoint, wherein Barry Allen went back in time and stopped his mother from being murdered. In the resulting timeline, Wally West is the Flash, Joe is an alcoholic who isn't in touch with his kids, Cisco is a billionaire who wants nothing to do with metahumans, [[ArsonMurderAndJaywalking Caitlin is a pediatric optometrist]], and the city is being terrorized by a speedster named The Rival. Flash eventually is forced to revert the timeline, only to find himself in one that is merely a CloseEnoughTimeline, which is played for much angst, as the new timeline features Cisco's brother dying in a car wreck, [[Series/{{Arrow}} John and Lyla]]'s child being a little boy named John instead of a girl named Sara, [[spoiler:Caitlin being a metahuman]], and Iris not talking with Joe.

* ''Series/GreysAnatomy'' has the episode "If/Then", revolving around Ellis Grey being both alive and lucid. There are fairly significant ripple effects (Alex has proposed to Meredith; Callie and Owen are married; the Shepherds are still together; Cristina has no friends) but Because Destiny Says So other things come back to bite them (Alex is still an inveterate womanizer; Mark and Addison are still carrying on; Meredith still can't please her mother; she and Derek are attracted to each other; she and Cristina become Fire-Forged Friends whilst struggling to save a patient, Callie and Arizona are drawn to each other), turning the whole thing from "For Want of a Nail" into "In Spite of a Nail" instead. Incidentally, the episode's theme is "Because Destiny Says So." Has a lot of moments of This example contains a YMMV entry. It should be moved to the YMMV tab.Fridge Brilliance.
* ''Series/HerculesTheLegendaryJourneys'' had an episode where Iolaus traveled to a parallel universe where Hercules is an evil tyrant, Ares is the god of Love and the other gods are of different things than they usually are.

* The ''Series/{{Sherlock}}'' ChristmasSpecial "[[Recap/SherlockSpecialTheAbominableBride The Abominable Bride]]" mostly takes place in a WhatIf scenario entirely in Sherlock's "Mind Palace" (with a "healthy" doze of drugs). It's a more traditional take on Franchise/SherlockHolmes, taking place in Victorian England, investigating the case of a woman who publicly committed suicide and then keeps appearing and killing men. [[spoiler:This is all Sherlock's attempt to figure out how Moriarty could have possibly survived shooting himself in the head a foot away from Sherlock. He comes to the conclusion that Moriarty is, of course, dead, but he has set events in motion prior to his death that still continue to unfold]].

** ''Series/StarTrekDeepSpaceNine'' has the episode "[[Recap/StarTrekDeepSpaceNineS06E13FarBeyondTheStars Far Beyond the Stars]]", where the cast are reimagined in 1950's New York. Sisko, Kira, Julian, Bashir & Quark are all writers for a science fiction magazine. Odo is their boss, Jadzia is his secretary and Martok is their artist. Cassidy is a waitress at a local diner, Jake is a petty criminal, Worf is a professional athlete, Weyoun and Gul Dukat are a duo of racist police officers and grandpa Sisko is a priest and possible hallucination. When Martok's counterpart shows "Benny" a sketch of Deep Space Nine, Benny decides to write a story about it. It is rejected for featuring a Black Captain, one Benjamin Sisko. Benny attempts to get the story published result in him developing an obsessive attitude towards his Deep Space Nine stories and eventually having a breakdown due to his powerlessness against the racist society around him. Sisko thinks of the whole thing as a vision from the Prophets about "fighting the good fight" even when things feel hopeless. Interestingly, despite each of the actors playing a character distinctly different from their main role, each still has elements of the original. Quark's counterpart is the most vocal supporter of publishing Benny's story and has a strong social conscience, yet he is still convinced to stay with the magazine after haggling for a pay rise and being called a socialist is his BerserkButton, for example. In later episodes, following a surprise narrative return to the "Benny reality", it is left ambiguous as to whether that reality might truly be the real one.

* ''Series/{{Supernatural}}'':
** Season 2 features an episode in which Dean encounters a [[OurGeniesAreDifferent Jinn]] and wakes up in a timeline where his mother was not killed by the YED and thus his father never became a hunter. Dean lives with his beautiful girlfriend and lives a modest life as a mechanic. He also finds out he is estranged from Sam, who is studying Law and Stanford and still with Jessica. Even though he is heavily implied to be an alcoholic and something of a screw-up, Dean finds this existence far better than his own, and he only sets about to return to the regular timeline when he realizes that all the people Sam, John and he saved are dead. [[spoiler: It turns out it was MentalWorld, created by the Jinn and not an actual alternate timeline.]]
** Season 4 has an episode where Sam and Dean are new employees at a hi-tech company, but have false memories of their lives and don't even know each other. While investigating a series of suicides at their company, they come to the conclusion that a ghost is involved and hunt it down. This leads Sam to first suggest that they should continue as ghost-hunters, and then realize that their whole apparent lives are fake. In the end, it turns out to be an illusion created by the angel Zachariah designed to inspire the [[DespairEventHorizon broken]] Dean to continue the life of a hunter.
** Season 6 features an episode where Sam and Dean drive a Mustang, Cuban is not communist and Jo and Ellen are still alive, with Ellen happily married to Bobby. It turns out that the ''Titanic'' never sank in this timeline and that led to numerous small changes that are arguably better than their normal CrapsackWorld. Unfortunately, this leads to the fates becoming enraged so the timeline must be set right.

** In "Yuletide Fortune Tellers", the girls are upset about their families' Christmas traditions only to wake up in a world where the switch never happened. Daphne is Bay, a star athlete with Toby a moody musician and John and Kathryn having marriage problems. Bay is Daphne, raised with a younger brother but Regina still drinking and Emmett only a friend.

* In the third season Christmas special for ''Series/{{Warehouse 13}}'', Pete is pulled into a world where he was never born, leading to Myka arresting Artie, Claudia never leaving the psych ward, and [[BigBad MacPherson]] taking over the Warehouse.

* ''Series/XenaWarriorPrincess'' saved the Fates in "[[Recap/XenaS02E02RememberNothing Remember Nothing]]" and was given a chance to live her life if she had never become a warlord and "When Fates Collide" when Caesar forces the Fates to change his fate making him and Xena rulers of Rome.

* ''WesternAnimation/ThePowerpuffGirls1998'' was to have an alternate reality episode, "Deja View," half of which was supposed to be in CGI, but it went over budget and was facing a tight deadline. The original story outline was given to DC Comics for issue #50 of [[ComicBook/ThePowerpuffGirls the PPG comic book]]. It had the girls sucked into a vortex and winding up in Townsville's alternate counterpart Viletown and the girls' alternate counterparts, the Powerpunk Girls, rending Townsville asunder.

* An odd variation on this trope occurs in the ''Series/{{Community}}'' episode "[[Recap/CommunityS3E04RemedialChaosTheory Remedial Chaos Theory]]". Jeff throws a dice to decide who goes to get pizza, and the time-line splits into seven different universes. While some of the differences are relatively small (e.g. in one universe Troy and Britta fall for each other much earlier, while in another Britta hooks up with the pizza delivery guy) one of them is extremely horrible. When Troy gets the pizza, Pierce gets shot in the leg and dies, the apartment catches fire, Troy eats a flaming troll doll and loses the ability to speak, Jeff loses his arm, Shirley succumbs to alcoholism, Annie gets committed to a mental institution, [[ArsonMurderAndJaywalking and Britta dyes a streak of her hair blue]]. Abed dubs this "The Darkest Timeline" and makes everybody fake beards.

** Played ''terrifyingly'' in "[[Recap/BuffyTheVampireSlayerS3E9TheWish The Wish]]". Cordelia, bitter over her failed relationship with Xander, makes an idle wish that Buffy had never come to Sunnydale, believing that her [[AlphaBitch popular status]] would still be intact if she had never gotten involved in the Scoobies' affairs; unfortunately, she speaks in front of a disguised vengeance demon who [[BeCarefulWhatYouWishFor grants her wish to the letter]]. Cordelia is tossed into a [[CrapsackWorld crapsack]] alternate universe where the Sunnydale population is a tenth of what it was, due to unchecked vampire attacks, due in turn to the Master having ascended a year and a half before without Buffy there to stop him. Cordelia is killed by evil vampire versions of Willow and Xander, Giles and Oz are trapped in thankless work as desperately outnumbered vigilantes attempting to do what they can to restore some semblance of safety to the community, Angel is kept in a cage with the Master's minions allowed to torture him for fun, and Buffy eventually makes an appearance as a hardened, pitiless rogue Slayer who has gone off the deep end without her friends' humanizing influence. The episode ends with a vicious FinalBattle in which the entire main cast kills each other; Giles' last-minute actions save the day and propel everyone back into their proper reality, but it's still incredibly frightening.

** Played with in "[[Recap/BuffyTheVampireSlayerS6E8TabulaRasa Tabula Rasa]]", where Willow casts a spell intended to remove Tara's memory of breaking up with her but instead blanks out everyone's memories including her own. They're in the same universe but because they're all starting from a blank slate they reach some very different conclusions about themselves. Giles and Anya think they're married, Spike thinks he's a vampire with a soul (usually Angel's role) and Buffy finds being a Slayer cool.
** "[[Recap/BuffyTheVampireSlayerS6E17NormalAgain Normal Again]]" had Buffy, under the effects of a demon's venom, flashing between the normal Buffyverse, and an alternate universe where she had spent the last seven years catatonic in an insane asylum in Los Angeles, where they have been trying to treat her for her insane delusions about fighting vampires. [[AmbiguousSituation The episode makes no attempt whatsoever to clarify which, if either, of Buffy's perceived realities are the real thing.]]
** The spin off ''Series/{{Angel}}'' had "[[Recap/AngelS03E11Birthday Birthday]]", where Cordelia got a chance to make her life what it would have (or ''should'' have according to the one offering her the choice) been like [[ForWantOfANail if she had met a big-time talent agent instead of Angel in the pilot]]. She becomes famous but Angel gets the visions (because Doyle still died) and it drives him mad. Wes and Gunn are with him, but with only three arms between the two of them.

** This reality (dubbed "the Iron Bastille AU" by {{the wiki|Rule}}, after Joe's alternate title) was revisited in "Iron Bastille vs. Spitfire Moon", where Katrina enters the WVBA under the name Spitfire Moon (in the main reality, her boxing title is Chaton Cheri) after escaping her aunt to find her father. She and Iron Bastille have a spat with each other, where Bas denies ever having a child.

* ''Mirrored'', the IDW comics' New-Trek-Movieverse version of "Mirror, Mirror" had more in common with ''Series/StarTrekEnterprise'''s "In A Mirror Darkly" than the Original Series episode. It opens and closes with "our" Scotty and [=McCoy=] discussing the concept of alternate universes, and the rest of the story is set entirely in the MirrorUniverse, with no "real" characters. (Well, Old Spock seems to have come from [a version of] the regular universe rather than the mirror one, but he's still not the ''same'' Old Spock.)

** Season 2 features an episode in which Dean encounters a Jinn and wakes up in a timeline where his mother was not killed by the YED and thus his father never became a hunter. Dean lives with his beautiful girlfriend and lives a modest life as a mechanic. He also finds out he is estranged from Sam, who is studying Law and Stanford and still with Jessica. Even though he is heavily implied to be an alcoholic and something of a screw-up, Dean finds this existence far better than his own, and he only sets about to return to the regular timeline when he realizes that all the people Sam, John and he saved are dead. [[spoiler: It turns out it was MentalWorld, created by the Jinn and not an actual alternate timeline.]]

* ComicBook/TheTransformers has “Instruments of Darkness”, set in a BadFuture where Unicron devoured Cybertron and Galvatron now rules over a decimated Earth. Though it avoids being total filler when [[spoiler: The main universe’s Unicron has his minions teleport Galvatron to serve him at the end of the issue]].

* ''Series/DoctorWho'': In [[Recap/DoctorWhoS30E11TurnLeft "Turn Left"]], an alternate universe is created around Donna Noble where she never met the Doctor, and as a result, [[Recap/DoctorWho2006CSTheRunawayBride he died that Christmas stopping the Racnoss Empress]], which led to Donna losing her job, although she did win a trip out of town for the next Christmas. Good thing, too, because without the Doctor there to help [[Recap/DoctorWho2007CSVoyageOfTheDamned London was nuked]] and everyone in the city died. Because he wasn't there, [[Recap/DoctorWhoS29E1SmithAndJones almost everyone in the Royal Hope Hospital suffocated when it was transported to the Moon]], including Martha Jones — who never met the Doctor in this timeline — and [[Series/TheSarahJaneAdventures Sarah Jane and her friends]], who stopped the sabotaged MRI from going off. It goes FromBadToWorse: The Doctor and Donna weren't there to [[Recap/DoctorWhoS30E1PartnersInCrime stop the Adipose]], and tens of millions of Americans were killed. [[Recap/DoctorWhoS30E4TheSontaranStratagem The Sontarans nearly succeeded]] [[Recap/DoctorWhoS30E5ThePoisonSky in rendering the planet inhospitable]], saved only by the heroic sacrifices of the Series/{{Torchwood}} team. And ''then'' [[TheStarsAreGoingOut the stars go out.]]

* The ''Series/{{Sherlock}}'' ChristmasSpecial "[[Recap/SherlockSpecialTheAbominableBride The Abominable Bride]]" mostly takes place in a WhatIf scenario entirely in Sherlock's "Mind Palace" (with a "healthy" doze of drugs). It's a more traditional take on Sherlock Holmes, taking place in Victorian England, investigating the case of a woman who publicly committed suicide and then keeps appearing and killing men. [[spoiler:This is all Sherlock's attempt to figure out how Moriarty could have possibly survived shooting himself in the head a foot away from Sherlock. He comes to the conclusion that Moriarty is, of course, dead, but he has set events in motion prior to his death that still continue to unfold]].

* ''WesternAnimation/ThePowerpuffGirls'' was to have an alternate reality episode, "Deja View," half of which was supposed to be in CGI, but it went over budget and was facing a tight deadline. The original story outline was given to DC Comics for issue #50 of the PPG comic book. It had the girls sucked into a vortex and winding up in Townsville's alternate counterpart Viletown and the girls' alternate counterparts, the Powerpunk Girls rending Townsville asunder.

* ''Manga/OnePiece'' has several anime only episodes that presents the characters living in Feudal Japan instead of their own world.

* Creator/MarvelComics' take on alternate reality storytelling was its long-running ''What If?'' title.

* ''WesternAnimation/{{Ben 10}}'' has an episode, "Gwen 10" where, surprisingly, it's Gwen who gets the omnitrix, not Ben. It's framed by a benevolent narrator explaining how stories can be told different ways.

* ''Series/{{Supernatural}}'' has an episode where Sam and Dean are new employees at a hi-tech company, but have false memories of their lives and don't even know each other. While investigating a series of suicides at their company, they come to the conclusion that a ghost is involved and hunt it down. This leads Sam to first suggest that they should continue as ghost-hunters, and then realise that their whole apparent lives are fake. In the end, it turns out to be an illusion created by the angel Zachariah designed to inspire the [[DespairEventHorizon broken]] Dean to continue the life of a hunter..

** [[Recap/BuffyTheVampireSlayerS3E16Doppelgangland Dopplegangland]] was a play on this trope. Vampire!Willow from the alternate reality of The Wish accidentally finds her way to the real world, setting some serious {{foreshadowing}} for further seasons.

** [[Recap/BuffyTheVampireSlayerS6E17NormalAgain Normal Again]] had Buffy, under the effects of a demon's venom, flashing between the normal Buffyverse, and an alternate universe where she had spent the last seven years catatonic in an insane asylum in Los Angeles, where they have been trying to treat her for her insane delusions about fighting vampires. [[AmbiguousSituation The episode makes no attempt whatsoever to clarify which, if either, of Buffy's perceived realities are the real thing.]]

* The ''Series/{{Sherlock}}'' ChristmasSpecial "The Abominable Bride" mostly takes place in a WhatIf scenario entirely in Sherlock's "Mind Palace" (with a "healthy" doze of drugs). It's a more traditional take on Sherlock Holmes, taking place in Victorian England, investigating the case of a woman who publicly committed suicide and then keeps appearing and killing men. [[spoiler:This is all Sherlock's attempt to figure out how Moriarty could have possibly survived shooting himself in the head a foot away from Sherlock. He comes to the conclusion that Moriarty is, of course, dead, but he has set events in motion prior to his death that still continue to unfold]].

** ''Series/StarTrekTheNextGeneration'': In "Yesterday's Enterprise", the USS ''Enterprise''-C is flung into the future thanks to a temporal anomaly while fighting off Romulans attacking a Klingon planet. The ''Enterprise''-C finds that thanks to the time warp, the Federation is in a losing war with the Klingon Empire, who were insulted by the apparent cowardice of Starfleet. In this timeline, the ''Enterprise''-D is a full-fledged warship without any civilians aboard, except Guinan, [[RippleEffectProofMemory who's the only one who realizes that something's wrong]], and Tasha Yar, who'd died in season 1, is alive in Worf's place as chief tactical officer.

* ''Series/{{YoungSheldon}}'' S4 E17 "A Black Hole" shows three alternate realities: