History AbortedArc / WesternAnimation

* Birdboy's debut episode in ''WesternAnimation/{{Birdman}}'' ended with Birdman promising to help him [[DisappearedDad find his father]], and the search was occasionally brought up in Birdboy's later appearances. However, nothing ever came of it.

* In the StoryArc of Season 20 of ''WesternAnimation/SouthPark'', nostalgia-powered sentient fruit called Member Berries are threatening a conspiracy that Randy Marsh eventually finds out about and teams up with Presidential nominee Mr. Garrison to stop. Unfortunately, the conclusion to this arc relied on [[DeweyDefeatsTruman the presumption that Hillary Clinton would win the current election]]. [[RealLifeWritesThePlot When Donald Trump, whom Garrison was serving as a proxy for, won instead]], the plot is abruptly stopped by Garrison and Randy brainwashed by the Member Berries. The Member Berries then get to stay in the White House and [[WhatHappenedToTheMouse nothing is done about them in the end.]]

* ''WesternAnimation/GeneratorRex'': The crossover with the ''Ben 10'' series hinted at the possibility Rex and Ben will meet again. Unfortunately, mostly due to Derrick J Wyatt disliking ''Generator Rex'', this was never followed up in ''Omniverse''. The [[WesterAnimation/Ben102016 Ben 10 reboot]] would have a much younger Ben meet a different Rex.

* ''WesternAnimation/ToddMcFarlanesSpawn'': A Season 1 episode introduced a minor subplot about Comicbook/{{Angela|Marvel Comics}}, a warrior from Heaven who voiced her intention to hunt down and kill Spawn. Due to the notorious legal battle between Creator/ToddMcfarlane and Creator/NeilGaiman over ownership of the character, Angela never appeared on the show again, necessitating the creation of a [[SuspiciouslySimilarSubstitute similar character]] named Jade.

** "The Unstoppable Juggernaut" ends with Comicbook/{{Colossus}} declining an offer to join the team and saying that he intends to travel the country to find Comicbook/{{Illyana|Rasputin}}, his missing little sister. The next time Colossus shows up, he's still in New York, and Illyana is safely in Russia with their parents. There's no further mention of her supposed disappearance, and nothing to indicate she's ever even ''been'' to America.

* Thanks to its sudden cancellation during halfway of Season 9, ''WesternAnimation/AdventureTime'' had to hastily tie up four plotlines (Finn and Fern, Gumbald, Simon and Betty and GOLB) at once with "Come Along With Me". Had the series not been cancelled, the rest of the episodes would've focused more on Gumbald and his plans, as well as Minerva, Susan Strong and Sweet P. The Simon and Betty/GOLB plotlines were also originally planned to be part of the real finale of the show before being reworked into what we got today.

* ''WesternAnimation/{{Spawn}}'': A Season 1 episode introduced a minor subplot about Comicbook/{{Angela|Marvel Comics}}, a warrior from Heaven who voiced her intention to hunt down and kill Spawn. Due to the notorious legal battle between Creator/ToddMcfarlane and Creator/NeilGaiman over ownership of the character, Angela never appeared on the show again, necessitating the creation of a [[SuspiciouslySimilarSubstitute similar character]] named Jade.

** Finn's love life has been one of the most notorious plot threads among the fans since the beginning of the series, with the amount of teasing, confirming ships and sinking them seasons or episodes later, which caused a lot of anger and frustration with shippers. It happened with Princess Bubblegum, and it happened again with Flame Princess. And once the show finally did something between him and Huntress Wizard, the finale ''and'' the ''[[WesternAnimation/AdventureTimeDistantLands Distant Lands]]'' miniseries completely ignored their relationship. While the former suffered because of the cancellation, the latter had no reason to ignore this plot thread since the miniseries gives closure to the main characters, which ended up frustrating fans who waited years for some resolution.

** The episode "Into the Wand" has Star learn hints about her mother's backstory, as well as that of three other queens of Mewni: [[AmbiguouslyEvil Eclipsa the Dark]], [[WarriorPrincess Solaria the Monster-Carver]] and [[ShrinkingViolet Celena the Shy]]. Eclipsa becomes a major character in the last two seasons, Solaria is important to the backstory of the final BigBad, but Celena, and the comments about her [[TheseAreThingsManWasNotMeantToKnow hiding "cosmic secrets,"]] are never really expanded on. ''Literature/TheMagicBookOfSpells,'' published about two years later, [[LeaningOnTheFourthWall slightly calls attention to this]] in Celena's chapter, as Star's implies that she doesn't actually know any that important.

* ''WesternAnimation/DannyPhantom'' had this in spades, due to co-producer Steve Marmel departing the show before its final season, with the show's writing team getting replaced as well.[[note]]Or Marmel was straight-up fired over his and creator Butch Hartman's creative differences, with the writers also getting the boot. It's unclear.[[/note]] Butch Hartman and the new writers had little interest in resolving anything outside Danny and Sam's WillTheyOrWontThey for the final season, with the biggest loose ends being:

** Gwen's friendships with both Bridgette and Leshawna in ''Island'' were pretty much forgotten by the end of ''Action'', as she started interacting more with Courtney (whose friendship with Bridgette was also forgotten after ''Island'') and Duncan while Bridgette (who fell completely OutOfFocus) became more and more defined by her relationship with Geoff and Leshawna by her on-and-off romance with Harold.
*** The same applies with numerous other friendships from the first season. Duncan's friendship with Geoff and DJ was ignored after the first season, as the latter two fell OutOfFocus (with Geoff becoming increasingly defined by his relationship with Bridgette) and Duncan started to interact more with Gwen and Courtney in the immensely controversial LoveTriangle. Similarly, Owen's friendships with Cody and Trent were abandoned for an OddFriendship with Noah as Trent fell OutOfFocus after his breakup with Gwen and Cody became increasingly defined by his status as part of a love triangle with Gwen and Sierra in ''World Tour''.

* ''Every'' set of producers for the Creator/{{Hasbro}}-owned ''Franchise/{{Transformers}}'' had to deal with never knowing if their incarnation of the franchise be renewed or not, and every series got wrapped up in a hurry when the plug got pulled with little notice. Plot lines would also change suddenly, due to the desire of higher-ups to push new toys and promotions. (This can potentially apply to every MerchandiseDriven series.)

*** That said, some of ''Prime'''s storylines (especially in surrounding media) fell into this. Reading the tie-in novels, one finds them heavily building up the threat of the SpacePirate Star Seekers and their captain, Thundertron, who even received a toy at mass retail. This was building up to the Star Seekers showing up and becoming antagonists in the series... which never actually happened.

* ''WesternAnimation/TheSimpsons'': Krusty the Clown was originally intended to be Homer Simpson in disguise in order to set up a story where Bart finds out that the clown he loves and idolises so much is actually his father (whom he doesn't get along with). This is why Krusty the Clown has Homer Simpson's exact body shape. However, this was dropped when the writers realised that Krusty would no longer work as a character once the twist were revealed to the audience. Instead, Krusty became just another Simpsons character and was used to satirise children's entertainers who pretend to be nice when in character are but are actually [[NiceCharacterMeanActor depressed, trashy and corrupt behind the scenes]].

* ''WesternAnimation/DuckTales2017'': "The Duck Knight Returns!" ends on a {{cliffhanger}} where Jim Starling is revealed to have survived the explosion, and becomes Negaduck. However, he is never seen again after this episode, not even in the final season special "Let's Get Dangerous!". Frank Angones ''did'' state that "I didn't want to shortchange him" and that he had a big story planned for him in a later season, but the series' cancellation after season 3 ultimately prevented it.

* ''WesternAnimation/Ben10UltimateAlien'': Three arcs fell victim to this; the lingering threat of King Viktor, the redemption journey of Charmcaster (whose true name is [[spoiler: Hope]]), and the possession of Elena Validus by the Hive nanochips. This was because then-series producer [[AuthorExistenceFailure Dwanye McDuffie passing away]] during production. The people placed in charge of [[WesternAnimation/Ben10Omniverse the following series]] outright stated they had no interest in continuing them. While that first plot got some satisfying closure through Dr. Viktor becoming himself again ([[AuthorsSavingThrow with Zs'Skayr being shown removing Xarion's soul and allowing Viktor to regain control]]), the others didn't. Elena cameoed as herself toward the end of the series with no explanation as to how she was freed of the nano chips' influence, while Charmcaster never went by her true name again and saw no escape from the HeelFaceRevolvingDoor (as the answer for what side she'd finally land on was to happen in a proposed SpinOff starring Ben's cousin Gwen, who is Charmcaster's main rival).

* ''WesternAnimation/DuckTales2017'': "The Duck Knight Returns!" ends on a {{cliffhanger}} where Jim Starling is revealed to have survived the explosion, and becomes Negaduck. However, he is never seen again after this episode, not even in the final season special "Let's Get Dangerous!".

** ''WesternAnimation/BeastWars'' mostly avoided this and, even after the third season turned out to be the last, managed to wrap things up pretty well, with the only major plotline to be truncated being Tarantulas and his feud with the Vok. It did, however, have a weird case of this where the beginning and resolution of an arc are there, but the middle part explaining how they’re connected got left out; season two has Dinobot back up his memories aboard the Axalon’s computer shortly before [[spoiler:he dies]] and in the finale, his evil clone [[spoiler:gains those memories after his connection to Rampage is severed]]. There was supposed to be an episode connecting those events where Rattrap would try to upload the back-up memories into the clone, but it’s script was rejected and the episode went unproduced, leaving the clone’s fate in the finale a bit inexplicable.

* In ''WesternAnimation/SheRaAndThePrincessesOfPower'', part of Adora's motivation is that she wants to find her family. There are a few twists in it along the way, such as the discovery that she's a [[{{Precursors}} First One]]. She seemingly forgets entirely about it in the fifth season, and while an answer is ''given'', namely that the First Ones have apparently been wiped out by Horde Prime, a) it doesn't really seem to affect Adora one way or the other, b) the indication that this happened some time ago leaves a big old question about where Adora came from, and c) even when there ''is'' a scene that could have had her realising that her real family is her TrueCompanions, it's never actually stated.
** Then there's the revelation that the First Ones were not as benign as we'd been led to believe, with the Sword of Protection being a PowerLimiter rather than the source of She-Ra's power, in addition to being the key to their superweapon. There's a flashback scene where Madam Razz teaches Mara to access some of her powers without needing to transform. Finally, in the season 4 finale, Adora cuts ties with Light Hope and the First Ones [[spoiler: and shatters the sword to stop it from being used again]]. The first few episodes of season 5 have Adora struggling with the consequences of that decision. Rather than expanding on that foreshadowing, maybe have Adora seek out the legacy of She-Ra beyond what Light Hope had told her, explore new aspects of her powers, or anything like that, she just [[spoiler: magics up a new sword and gets a new outfit]], and the arc of season 5 continues its focus on the First Ones, just expanded to include their relation to Horde Prime's forces.
** On a smaller scale, the Star Siblings get an episode dedicated to their introduction, culminating in them agreeing to join Adora's cause rebelling against the Horde. The only other time they're seen is on a monitor on Horde Prime's ship, with an offhand comment that other worlds are rebelling. There's no indication that this has any impact on the war, with all the major battles taking place on Etheria, and while it would tie into the theme of needing to work together, the battle ultimately comes down to [[spoiler: Horde Prime versus Adora- charged up by the PowerOfLove]], so teamwork apparently wasn't that important either.

** ''WesternAnimation/TransformersAnimated'', though ending fairly conclusively, had a bevy of plot threads LeftHanging, included Meltdown making a return, [[spoiler:Waspinator and Blackarachnia getting stranded on an island]], where [[spoiler:Sari's protoform came from]], and both Lockdown and Swindle [[spoiler:escaping]]. It should be noted that the cancellation that resulted in a number of these plots threads being unresolved was a mix of Hasbro's ExecutiveMeddling and being ScrewedByTheNetwork.[[note]]''Animated'''s last season was produced as Hasbro and [[Creator/DiscoveryChannel Discovery Communications]] were planning to combine forces and create their own kids channel called [[Creator/DiscoveryFamily The Hub]]. Creator/CartoonNetwork shared the rights of the ''Animated'' show with Hasbro, due to that incarnation being produced by their in-house studio. The end result was that Hasbro did not desire to continue the series when they [[WesternAnimation/TransformersPrime could just make a new one that they'd completely own]], and while Cartoon Network was given the option to continue ''Animated'' solo, they saw no point if they could no longer merchandise it.[[/note]]

* ''WesternAnimation/DannyPhantom'' had this in spades, due to co-producer Steve Marmel departing the show before its final season, with the show's writing team getting replaced as well.[[note]]Or Marmel was straight-up fired over his and creator Butch Hartman's creative differences, with the writers also getting the boot. It's unclear.[[/note]] Butch Hartman and the new writers had little interest in resolving anything outside Danny and Sam's WillTheyWontThey for the final season, with the biggest loose ends being:

** Season 4 had a recurring subplot about The Mane Six rebuilding The Castle of the Two Sisters, Princess Celestia and Luna's old home, implying it may be used as a new base of sorts for their future adventures down the line. But after Twilight gets [[MerchandiseDriven her own castle]] in the season finale, this plot is immediately forgotten and the old castle only comes up once at the end of season 5. And only in the BadFuture where Nightmare Moon took over where it was being used as her personal throne, with no comment made regarding what happened to the one in the mane universe.

* Many episodes of TheSimpsons begin with the family embarking upon one task or adventure only for their priorities to abruptly switch to something else with no further mention made of the thing they began the episode doing. This is often lampshaded. In “Simpsons Safari,” for instance, the plot begins with Homer instigating a bag boy strike at the grocery store, an arc which is then promptly abandoned as the family travels to Africa. Ages later, as the family hurtles down a river in a makeshift boat heading straight for Victoria Falls, Homer randomly muses “So, you think they settled that bag boy strike yet?”

* ''WesternAnimation/DannyPhantom'' had this in spades, as no one expected that the show would be ending with three seasons. The major ones are:
** Anything involving [[BigBad Vlad]]. Those being his plans with Fright Knight, the Crown of Fire, his ElaborateUndergroundBase, and his acquirement of Axion Labs.
** The return of [[FutureMeScaresMe Danny's evil older self]], which was heavily hinted at at the end of his sole appearance, with one of the head writers outright stating that they did have more stories with him planned, including being the FinalBoss of the series.
** The show's penultimate episode has Valerie discover that [[spoiler:her employer Vlad and Danny's "cousin" Danielle are half-ghost]]. The episode ends with her saying that she plans to do something with this revelation. The series finale makes no mention of this plotline whatsoever, with Valerie herself only getting two non-speaking background cameos.
** 10 years later, Butch Hartman confirmed that had a fourth season occurred, Danielle would have been HappilyAdopted by the Fentons, becoming Danny and Jazz's little sister.

** A recent announcement was made of a ''WesternAnimation/DarkwingDuck'' reboot in the works at Disney, however, potentially hints at a future appearance.

** Near the end of the fourth and final of the direct to DVD films, "Into The Wild Green Yonder", The Encyclopod, a massive creature that collects specimens of endangered species around the universe, adds some human DNA to its collection. But when Fry questions why it did so if it only collects DNA, it simply leaves without comment and after the series revival, this is never picked up on.

* ''WesternAnimation/MiraculousLadybug'': [[AlphaBitch Chloé's]] character arc. Several episodes seemed to plant the seeds for a potential redemption by showing signs of a HiddenHeartOfGold and having her regret some of her actions, and she eventually [[spoiler:became a Miraculous wielder under the name Queen Bee]]; however, during season 3, any idea of a redemption arc was dropped when she became ''even worse'' than she had in previous seasons, even [[spoiler:willingly allying with [[BigBad Hawk Moth]] when she doesn't get her way]]. What the writers plan on doing with her now is currently unknown.

* ''WesternAnimation/BoJackHorseman'':
** Despite the pictures of [=BoJack=] having sex with Sarah Lynn being given some build up, they were mostly used for a few comedic moments before being resolved very simply without much thought given to them. How much do the paparazzi demand to prevent the photos from leaking? [[spoiler:$150. Each.]]
*** This comes back to light around the final season, which bites Bojack in the ass big time.
** Played for comedy when Todd gets $8 million at the end of season 3. He starts wondering what [[LeaningOnTheFourthWall interesting adventures that could lead to]], but in the very next scene, he intentionally gives it all away, making him poor again.

* ''WesternAnimation/Ducktales2017'': "The Duck Knight Returns!" ends on a {{cliffhanger}} where Jim Starling is revealed to have survived the explosion, and becomes Negaduck. However, he is never seen again after this episode, not even in the final season special "Let's Get Dangerous!".
** A recent announcement was made of a ''WesternAnimation/DarkwingDuck'' reboot in the works at Disney, however, potentionally hints at a future appearance.