History Main / RequiredSpinoffCrossover

* ''Series/SamAndCat'' has the Robbie character from ''Series/{{Victorious}}'' show up in Episode 4.

* ''VideoGame/AngryBirds'' has it both ways. The spinoff ''VideoGame/BadPiggies'' features a cameo from the Blue Birds in the episode "When Pigs Fly", and the birds themselves can be found sleeping in "Flight in the Night". Meanwhile, ''Angry Birds'' itself debuted a new episode entitled "Bad Piggies", which features the same setting and characters as the game it is named after.

** ''Series/LawAndOrderSpecialVictimsUnit'' had Briscoe and Green from ''Series/LawAndOrder'' investigating a case that tied into Benson and Stabler's in "...Or Just Look Like One," and Abbie Carmichael served as the ADA in charge of SVU cases until they got their own ADA (first a minor character played by Reiko Aylesworth, then Alex Cabot). Furthermore, there was a crossover episode with the mothership, "Entitled," where SVU investigated the case in one episode and the DA's office prosecuted it in the next.

* From ''Series/TheGoldbergs'', Beverly Goldberg makes cameos in the PoorlyDisguisedPilot "1990-Something," which then became ''Schooled'', which also featured a cameo by Beverly in the first episode.

* As the page quote indicates, ''WesternAnimation/TheSimpsons'' mocks this idea in the ''Chief Wiggum, P.I.'' segment of "The Simpsons Spin-Off Showcase."

* In ''WesternAnimation/TheClevelandShow'', one one-off gag features Chris appearing in Cleveland's house for no reason. ("Go back to Quahog!") Another episode features the death of Cleveland's ex-wife as an important plot point, giving an excuse for Quagmire and Peter to show up. Cleveland and his family also reappeared in a ''WesternAnimation/FamilyGuy'' episode. And following the cancelation of their own show, Cleveland and his family moved back to his old place in Quahog

* To celebrate the franchise's 15th anniversary, several episodes of ''Anime/HugttoPrettyCure'' feature characters from the previous 14 seasons, but the most frequent characters to appear are Cure Black and Cure White from ''Anime/FutariWaPrettyCure''.

* ''Series/TheBookOfBobaFett'' has Fett and his NumberTwo Fennec Shand agree that they need some more muscle, so they decide to reach out to an acquaintance known as "Series/TheMandalorian". The next episode kicks off a three-part crossover between the two shows, each part of which even lists [[Creator/PedroPascal the Mandalorian's actor]] as the third-most important cast member in the end credits (behind the respective actors of [[Creator/TemueraMorrison Boba]] and [[Creator/MingNaWen Fennec]]). Notably, the crossover both resolves the main threat in ''The Book of Boba Fett'', and prepares Mando's clan for their own show's third season.

** Big Bird made a prominent appearance with Leslie Uggams. At one point, Big Bird talks to Miss Piggy, who derisively calls ''Sesame Street'' "that cute little children's show with puppets", and Big Bird laughs at the thought of her being in love with Kermit, and nearly misses a karate chop from her.

*** ''Voyager'' character Tuvok appeared in one of ''Deep Space Nine'''s AlternateUniverse episodes since the differences in timelines means that there was no reason for that version of the character to be trapped in the Delta Quadrant like the main universe version.

* ''Series/DoctorWho'' occasionally does this in reverse, with Capt. Jack returning and revealing his connection to Series/{{Torchwood}} in the last three episodes of Series 3, and Torchwood and [[Series/TheSarahJaneAdventures Sarah Jane]] getting caught up in the Series 4 finale. The producers went on record to say that the Doctor would ''never'' appear in ''Torchwood'', as that would encourage Who's younger fans to watch a show which, given its DarkerAndEdgier and HotterAndSexier nature, isn't exactly aimed at them.

* ''Series/DoctorWho'' occasionally does this in reverse, with Capt. Jack returning and revealing his connection to Series/{{Torchwood}} in the last three episodes of Series 3, and Torchwood and [[Series/TheSarahJaneAdventures Sarah Jane]] getting caught up in the Series 4 finale. The producers went on record to say that the Doctor would ''never'' appear in ''Torchwood'', as that would encourage Who's younger fans to watch a show which... [[DarkerAndEdgier isn't exactly]] [[HotterAndSexier aimed at them.]]

*** Willow was the crossover once again in the season 9 comic series, appearing on the last page of Angel&Faith #10.

* Aversion: ''Series/FamilyMatters'' (also known as "[[SpotlightStealingSquad The Urkel Show]]") never crossed over with its predecessor, ''Series/PerfectStrangers'', though it [[WhatCouldHaveBeen was planned]]. One wonders what kind of antics [[FunnyForeigner Balki]] and [[ExtravertedNerd Urkel]] would've gotten into.

* ''Manga/ACertainScientificRailgun'''s spin-off protagonist Mikoto Misaka will (most of the time) run into the series protagonist [[LightNovel/ACertainMagicalIndex Touma Kamijou]]. And most of the time, Mikoto WILL challenge Touma because of his [[{{AntiMagic}} Right hand]] cancelling her Railgun. And they'll tie. Inevitable, considering the two series run in the same timeline and several arcs connect to each other, such as the Sister's Arc.

* ''Webcomic/EerieCuties''[=/=]''Webcomic/MagickChicks'': The latter began as a SpinOff of the former and eventually took on a life of its own, with a greater emphasis [[DarkerAndEdgier on drama]], [[CharacterDevelopment character development]], and overarching storylines. Meanwhile, ''Eerie Cuties'' remained a lighthearted comedy/horror series. Despite this, characters from both series often [[TheCameo make appearances]] in the other and there's been two major crossover mini-arcs.

* {{Averted}} with ''WesternAnimation/BeavisAndButthead'' and ''{{WesternAnimation/Daria}}''. While there were plans to do a crossover, it quickly became apparent that the drastically different tones of the two shows meant there was little audience overlap, and thus not much to gain from doing one. Nowadays, many people don't even realize that the shows are related -- the only reference to ''B&B'' in ''Daria'' is from the first episode, when Helen mentions that they moved to Lawndale from Highland, the fictional Texas town where ''B&B'' took place. Even {{Flashback}}s to Daria's childhood don't make the connection.

* WesternAnimation/{{SpongeBob|SquarePants}} and Squidward ocassionally show up on ''WesternAnimation/ThePatrickStarShow''. [=SpongeBob=] is younger, although mostly the same; he's still Patrick's friend, still has Gary, still likes watching Mermaid Man and Barnacle Boy... the only difference is that it's unclear if he has a job (this is contradicted a few times). Squidward is a "neighborhood rando" (as identified by Patrick in "Pat-a-thon") who tries to collect money from Patrick's family as a newspaper deliveryman. As of "Super Sitters", they have four appearances each. Other main series characters like Mrs. Puff, Plankton, Mr. Krabs, and Pearl have each shown up once or twice.

* ''VisualNovel/AoiShiro'' has the appearance of Asama Sakuya from ''VisualNovel/AkaiIto'', who turns out to be Aoi-sensei's drinking buddy. The manga turn it UpToEleven by [[spoiler:making Wakasugi Tsudura and her group TheCavalry, with Hatou Kei's blood required to thwart Ba Rouryuu's plan]].

*** This was the entire premise behind the polarizing final episode "These Are the Voyages", which took BackForTheFinale UpToEleven by featuring not just Will Riker and Deanna Troi (and Data's voice) from ''Series/StarTrekTheNextGeneration'' (i.e. an entirely different ''series'' within the same franchise), but by reusing some old sets and footage from [=TNG=] and focusing the episode around a dilemma that Riker was facing in a [=TNG=] episode ("The Pegasus") that he decided to work through by reliving some scenes from the ''Enterprise'' era on the Enterprise-D holodeck.

See also PoorlyDisguisedPilot, an episode of the original series that's used to test the waters for a spinoff, and SpinoffSendOff, a crossover in the pilot of the spinoff to establish the connection with the previous series.

* WesternAnimation/{{SpongeBob|SquarePants}} and Squidward ocassionally show up on ''WesternAnimation/ThePatrickStarShow''. [=SpongeBob=] is younger, although mostly the same; he's still Patrick's friend, still has Gary, still likes watching Mermaid Man and Barnacle Boy... the only difference is that it's unclear if he has a job (this is contradicted a few times). Squidward is a "neighborhood rando" (as identified by Patrick in "Pat-a-thon") who tries to collect money from Patrick's family as a newspaper deliveryman. As of "Super Sitters", each of them have four appearances each. Other main series characters like Mrs. Puff, Plankton, Mr. Krabs, and Pearl have each shown up once or twice.

* WesternAnimation/{{SpongeBob|SquarePants}} makes a cameo in ''WesternAnimation/ThePatrickStarShow''.

** O'Neill's case makes a lot of sense, as he is currently the head of Homeworld Security, and the situation involving Project Icarus and ''Destiny'' are likely to need his oversight. You know, since Icarus Base was destroyed and most of the people in charge were killed or stranded on ''Destiny.''

** Lee Wuan Kai, a Korean assassin, had a history with Leon Vance, director of NCIS. So, naturally, her first stop was Los Angeles not long after they get established, causing Leon to fly out to deal with things [[ItsPersonal personally.]] Then she followed him back home.

** Seasons 2 and 3 of NCISNOLA also had two-part episodes that began on its parent show, indicating that this will be a yearly sweeps event.

* ''Series/TheBookOfBobaFett'' has Fett and his NumberTwo Fennec Shand agree that they need some more muscle, so they decide to reach out to an acquaintance known only as "Series/TheMandalorian". The next episode then exaggerates the trope, as despite the ''Boba Fett'' title card it's essentially a ''Mandalorian'' episode instead, following the title character and giving an update on his series' plot threads since the last time we saw him; and Fennec only shows up in the last minute of the episode to hire him. Mando gets gradually more involved with the main plot over the next two episodes, to the extent that the end credits for the whole crossover list [[Creator/PedroPascal his actor]] as the show's third most-important cast member; behind those of [[Creator/TemueraMorrison Boba]] and [[Creator/MingNaWen Fennec]].

* ''Series/TheBookOfBobaFett'' has Fett and his NumberTwo Fennec Shand agree that they need some more muscle, so they decide to reach out to an acquaintance known only as "Series/TheMandalorian". The next episode then exaggerates the trope, as despite the ''Boba Fett'' title card it's essentially a ''Mandalorian'' episode instead, following the title character and giving an update on his series' plot threads since the last time we saw him; and Fennec only shows up in the last minute of the episode to hire him. Mando gets gradually more involved with the main plot over the next two episodes, to the extent that the end credits list [[Creator/PedroPascal his actor]] as the show's third most-important cast member; behind those of [[Creator/TemueraMorrison Boba]] and [[Creator/MingNaWen Fennec]].

* ''Series/TheBookOfBobaFett'' has Fett and his NumberTwo Fennec Shand agree that they need some more muscle, so they decide to reach out to an acquaintance known only as "Series/TheMandalorian". The next episode then exaggerates the trope, as despite the ''Boba Fett'' title card it's essentially a ''Mandalorian'' episode instead, following the title character and giving an update on his series' plot threads since the last time we saw him; and Fennec only shows up in the last minute of the episode to hire him.

* As the page quote indicates, ''TheSimpsons'' mocks this idea in the ''Chief Wiggum, P.I.'' segment of "The Simpsons Spin-Off Showcase."