History Main / UnInstallment

* ''WesternAnimation/RickAndMorty'' has a Season 3 episode called "Vindicators 3: The Return of Worldender", but is the first episode of the series to feature the Vindicators. The first ''Vindicators'' installment is indicated by dialogue to have been one of Rick's and Morty's numerous offscreen adventures in the past ("we did it once, it was the big event of the summer"), and they find out later on that they weren't even ''invited'' to the second assembly (probably due to them all hating Rick), much to Morty's disappointment.

* A practical joke: Get three pigs. Paint them each with a number; 1, 2 and 4. Release them somewhere public and watch [[HilarityEnsues the fun]] as people try desperately to find #3. This is sufficiently well-known to the point where people familiar with the prank can be caught by surprise when there ''are'' four pigs.

* Not even the calendar is exempt from this. Upon announcing the transition from the Julian to the Gregorian Calendar in 1582, Pope Gregory XIII declared that the day following October 4 of that year would be October 15, essentially meaning that the days October 5-14, 1582 never existed. This was necessary because the problem with the Julian calendar was that its average year was too long, causing the calendar slowly fall behind the seasons, so skipping these 10 days was needed to correct this.

** A couple of years later in 2020, they would end up releasing the Samsung Galaxy S20 line, [[ExaggeratedTrope which skips numbers 11 to 19]].

* ''Nerd to the 3rd'', a podcast for Website/ThatGuyWithTheGlasses hosted by Dr. Gonzo, the Cat, and Travis, skipped over its 18th episode. Its 18th episode was later released as 'The Lost Episode', in which they discussed [[ExactlyWhatItSaysOnTheTin the series finale of]] ''Series/{{Lost}}'' with their guest Rollo T.

* WebVideo/SadPandaQAndA skips episode 8. Apparently, it had cameos by a number of Website/ThatGuyWithTheGlasses contributors, as well as WebVideo/TheAngryVideoGameNerd and [[WebAnimation/ZeroPunctuation Yahtzee]]. Episode 9 starts with Panda and Welshy unsure on how to follow it.

* The subtitle for the Music/{{Rush}} instrumental from Music/RollTheBones, "Where's My Thing" is "(Part IV, 'Gangster of Boats' [[TrilogyCreep Trilogy]])". There is no Gangster of Boats part I, II, or III.

* Both of Fantomas's first two albums skip the 13th track.

* Charles Ives composed two pieces titled Tone Roads No. 1 and Tone Roads No. 3. There is no Tone Roads No. 2.

* {{Music/ABC}}'s first album 'The Lexicon Of Love' contained "The Look Of Love [Part 1]" and "The Look Of Love [Part 4]". The song DOES have Parts 2 and 3, but they were only included on its 12" single.

* At the end of ''Comicbook/DarkCrisis: The Big Bang'', there's an updated list of the worlds in the multiverse by Barry Allen, who explains that he used [[WelcomeToTheRealWorld Earth-33]] comic books to help get a handle on them, explaining why several of them have issue numbers or titles after them. Curiously, Earth-46 is said to be home to "a grim young Batman with an unrecognizable rogues gallery" with the accompanying reference being ''Batman: The Gargoyle of Gotham''. There is no such comic, at least not in our world.

* For those outside of Japan, the ''Franchise/FinalFantasy'' games ended up like this due to several installments [[NoExportForYou never being localized]]; at first, SquareSoft renumbered the titles that ''did'' get a western release to avoid this issue, but in 1997 they gave up on this and jumped straight from ''III'' to ''VII'' (ironically creating a numbering gap between two subsequent installments--the first pair of subsequent installments to both get a western release, in fact). Later rereleases would restore the original, Japanese numbering scheme, and all of the missing games would also eventually make it to the West as well, in some form.

* The two terminals at Toronto's Pearson International Airport are named Terminal 1 and Terminal 3. There used to be a Terminal 2, but it was demolished in 2007 to make room for an expansion to Terminal 1, and Terminal 3 kept its name to avoid confusion. However, the airport authorities have not precluded the possibility of a future terminal building using the Terminal 2.

* The two terminals at Toronto's Pearson International Airport are named Terminal 1 and Terminal 3. There used to be a Terminal 2, but it was demolished in 2007 to make room for a expansion to Terminal 1, and Terminal 3 kept its name to avoid confusion. However, the airport authorities have not precluded the possibility of a future terminal building using the Terminal 2.

* ''Super Puzzle Fighter II Turbo''. There is no "Puzzle Fighter", "Puzzle Fighter II", or "Super Puzzle Fighter II". The title is meant to be a play on ''Super VideoGame/StreetFighterII Turbo'', the fifth iteration of the ''Street Fighter II'' sub-series.

** The episode "Awesom-o" mentioned a lost Lemmywinks sequel that never actually existed; the disclaimer claims it was lost because of the "disaster in Hawaii".

** Although it was just a joke, it led to various rumors about why there was no Volume Two. Two outtakes from Volume Three were bootlegged extensively before being officially released in 2007, and it was sometimes claimed that they were from the "missing" Volume Two. A fan theory also held that Music/TomPetty's ''Full Moon Fever'' and Music/RoyOrbison's ''Mystery Girl'' were collectively "Volume Two" - both albums were released between Wilburys albums, produced by Jeff Lynne, and included guest appearances by other Wilburys members, with only Music/BobDylan not appearing on either.

** For the longest time, the U-Bahn (subway) in Vienna, Austria, has lines U1, U2, U3, U4, and U6, because plans for the U5 were proposed in the 70s and 80s (when the system was being initially built), but none were approved. Construction on the U5 finally began in January 2021.

** The U-Bahn (subway) in Vienna, Austria, has lines U1, U2, U3, U4 and U6. U5 was supposed to be have been built, but the project never happened. U6 by this point had been completed, and nobody bothered to change the name.

[[JustForFun/IThoughtItMeant Not to be confused with]] CanonDiscontinuity.

* At the end of ''Comicbook/DarkCrisis: The Big Bang'', there's an updated list of the worlds in the multiverse by Barry Allen, who explains that he used [[WelcomeToTheRealWorld Earth-33]] comics to help get a handle on them, explaining why several of them have issue numbers or titles after them. Curiously, Earth-46 is said to be home to "a grim young Batman with an unrecognizable rogues gallery" with the accompanying reference being ''Batman: The Gargoyle of Gotham''. There is no such comic.

* Played for Laughs in ''WebAnimation/50WaysToDieInMinecraft''. Part 4 was originally skipped over and went ahead to Part 5. Part 4 was later added, with the in-universe explanation being that people were having literal [[FlameWar flame wars]] over the joke.

* The United States Navy has quite a few of these, where ship numbers for a given type will skip because a number was assigned but the ship was never built. In one case, CV-49 was the last carrier to see service until CV-59 was built nearly 10 years later(with the end of [=WW2=] causing the cancellation of the intervening carriers).

** It often references articles that don't exist. Typically this is its weekly "Next Week on Clickhole" (where the articles in question never appear), but also things like [[http://www.clickhole.com/article/we-would-make-following-corrections-our-13-hedgeho-1279 this list of corrections for the fictional "13 Hedgehogs Who Need A Vacation"]].