History ChuckCunninghamSyndrome / WesternAnimation

* In ''WesternAnimation/{{JumanjiTheAnimatedSeries'', the villainous "Stalker" character was introduced in the sixth episode, who looked somewhat like the Grim Reaper. The other villains feared and worked for him, which seemed to be setting him up as the main villain of the series. Unfortunately, he only appeared in two episodes and never reappeared, despite the ending of both episodes hinting at a reappearance.

* In the ''WesternAnimation/{{Jumanji}}'' cartoon, the villainous "Stalker" character was introduced in the sixth episode, who looked somewhat like the Grim Reaper. The other villains feared and worked for him, which seemed to be setting him up as the main villain of the series. Unfortunately, he only appeared in two episodes and never reappeared, despite the ending of both episodes hinting at a reappearance.

** Dr. Marvin Monroe, who appeared as a recurring character in the first six seasons of the show. In reality, his character was officially retired by the seventh season due to his voice being murder on Harry Shearer's throat. The in-universe explanation given was that Monroe had died, and his tombstone and a hospital named in his memory are seen in the background. He returns in the episode "Diatribe of a Mad Housewife" at Marge's book signing, where Marge is shocked to see he's alive. This trope is lampshaded, with Dr. Monroe giving the explanation "Oh, I've been very sick". He also has a speaking role in "Flanders' Ladder" in Season 29, albeit as a ghost.

** [[SitcomArchNemesis Ned Flanders]] and his family live in the house to the Simpsons' right, but what about the house to their left, 740 Evergreen Terrace? In the early seasons it was inhabited by an elderly couple, the Winfields. In the Season 4 episode "New Kid On the Block," they moved out, never to be seen again, and Ruth Powers and her daughter Laura moved in. Aside from that episode (largely revolving around Bart's PrecociousCrush on Laura) and the following season's "Marge on the Lam," which heavily featured Ruth, they never made another significant appearance, although Ruth would make frequent cameos in crowd scenes. Ruth's next spoken appearance is in season ''14,'' where Marge refers to her as her "old neighbor" and she mentions that she's been in prison. From there, the house is seen being inhabited by Ruth or is empty and prone to temporary residents DependingOnTheWriter. In Season 23's "The Wayz We Were," Ruth has this to say about the Simpsons as neighbors:

** {{Lampshade|Hanging}}d in an episode, where Rita and Runt are advertised as "Missing" [[FaceOnAMilkCarton on a milk carton]]. The "Rita and Runt" segments having been dropped in the latter half of the series' run, after which the characters themselves put in the occasional cameo appearance, but gradually disappeared - though they continued to feature in the opening credits, and were eventually restored for the direct-to-video movie ''WesternAnimation/WakkosWish'').

** Meg has a group of friends; Ruth, Esther, and Patty. In earlier episodes, however, a blonde girl named Beth was with them, but as of Season 6, she never appeared again - and was never able to develop further as a character as her other three friends have been developing lately.

** Quagmire's long-lost daughter Courtney meets Quagmire in Season 17's No Giggity, No Doubt and moves in with him but is never seen or mentioned again after that.

** Rarity's parents largely faded from the show after Season 4, only making a last background appearance in "A Hearth's Warming Tail" in Season 6 after having been absent throughout the intervening season, and a final cameo in the School For Gifted Unicorns in "The Ending of the End - Part 2". Their primary role in the show -- to serve as Sweetie Belle's caretakers -- is after that entirely taken over by Rarity, as Sweetie Belle is in most appearances shown living in Rarity's house rather than their parents', thus negating their only real narrative role.

** In the original run (1991-94), two slacker teenagers named Larry and Steve were seen from time to time with a different job in every appearance. After the show's hiatus, they disappeared; in a later episode, Larry appeared as a donut salesman - after that, he was never seen again.

** Early episodes had two - almost identical - characters called the Weasels do Nelson Muntz's bidding. Sometime around the third season, they disappeared and Nelson became friends with the Jimbo, Dolph and Kearney trio. The producers explained on the [=DVDs=] that six bullies felt like too many. They made their first appearance in years in "The Winter of His Content", where it's revealed they moved to Shelbyville.

** Feral's second-in-command Steel. He is last seen being chewed by Feral in "Enter the Madkat", and never reappears in the second season. It's been argued that Feral's niece, Felina, replaced Steel as her uncle's second in command, however they have different ranks and uniforms - Felina is only a lieutenant and Steel was a lieutenant ''commander''.

** In the first episode, arch-villain [[Comicbook/{{Deathstroke}} Slade]] is always seen with a silent butler standing at attendance - possibly Wintergreen, Slade's butler in the original ''Teen Titans'' comics. He is never seen with Slade after this episode, but if you look quickly, he is seen with the Brain's group of villains in the final season. (WordOfGod says that Slade was uninterested in joining, but sent Wintergreen as his representative.)

** At the end of "Homecoming - Part 2", the Doom Patrol parted with the Titans, claiming they would continue chasing after the Brotherhood of Evil (who had been their enemy up until that point). Then the Brotherhood put their full efforts targeting the Teen Titans and other younger superheroes, and the Doom Patrol are nowhere in sight, the Titans never try to contact them, and no one even directly mentions them.

* In ''WesternAnimation/TeenageMutantNinjaTurtles2012,'' the character of the Pulverizer/Timothy/Mutagen Man had completely disappeared from late season 3 onward. Despite Donatello ''promising'' to turn him back into a human, he's not even given a passing mention when Donatello creates the Retro-Mutagen. And is never seen (not even as a background cameo) or spoken of ever again.

** Rarity's parents largely faded from the show after Season 4, only making one last background appearance in "A Hearth's Warming Tail" in Season 6 after having been absent throughout the intervening season. Their primary role in the show -- to serve as Sweetie Belle's caretakers -- is after that entirely taken over by Rarity, as Sweetie Belle is in most appearances shown living in Rarity's house rather than their parents', thus negating their only real narrative role.

* ''WesternAnimation/OzzyAndDrix'': Ozzy and Drix are the only five of the original characters to from the original film to return, as Tom Colonic, Mayor Phlegmming, Leah Estrogen, The Chief, Mrs. Boyd, Bob and Shane were left out without any mention.

* In ''WesternAnimation/TheSmurfs'', we have [[OurMermaidsAreDifferent Marina the mermaid]], Handy's love interest, [[OurGeniesAreDifferent Gourdy the genie]] whose master is Farmer and the [[OurFairiesAreDifferent Pussywillow Pixies]]...

* WesternAnimation/StarVsTheForcesOfEvil:

* Though most of the characters from the movie made at the very least a cameo in the series once (even Scar did at one point under the name "Claudius"), Nala, the other lionesses, and young Simba (surprisingly) weren't in a single episode of ''WesternAnimation/TimonAndPumbaa'', though they did return in the sequels.

* ''WesternAnimation/XMenEvolution'': After the rise of Comicbook/{{Apocalypse}}, Comicbook/{{Sabretooth}} just disappears from the show. While its given a small HandWave courtesy of Pyro (claiming he was 'playing with a ball of yarn somewhere'), it's more of just Pyro rambling and doesn't mean a thing. Similarly, Destiny disappears in season 3 without any mention. When she last appeared she tells Comicbook/{{Mystique}} that she'll be involved in a plot to bring back an ancient mutant, but by Mystique's next appearence, she's working with Mesmero to bring back Apocalypse without any mention or reason.

** In the Seven Arts-era during the late [[UsefulNotes/LooneyTunesInTheSixties '60's]], some new characters were introduced, such as Cool Cat, Merlin the Magic Mouse and Bunny & Claude. While Cool Cat and his rival Colonel Rimfire sometimes appear in modern ''Looney Tunes'' works[[note]]specifically ''WesternAnimation/TheSylvesterAndTweetyMysteries'', ''WesternAnimation/TweetysHighFlyingAdventure'', and ''WesternAnimation/LooneyTunesCartoons''[[/note]] and Merlin eventually came back in ''WesternAnimation/TinyToonsLooniversity'' as Buster's mentor, Merlin's partner Second Banana and Bunny & Claude haven't really been seen since the Seven Arts-era. Justified, considering that the Seven Arts-era (and to a somewhat lesser extent, the [=DePatie-Freleng=] era) are widely considered the AudienceAlienatingEra of the series.

** Mermaid Man and Barnacle Boy were retired [[DiedDuringProduction after the death of]] Creator/ErnestBorgnine, who voiced the former, then the death of Creator/TimConway a few years later, who voiced the latter. Their final speaking appearance was in Season 9's "Patrick-Man!" From there on out, they were only seen in images (e.g. magazines, comic books). They did return in an episode of ''WesternAnimation/ThePatrickStarShow'', albeit as babies.
** Patrick's Sister Sam does't appear in the spin-off series ''WesternAnimation/ThePatrickStarShow'', instead in this series, Patrick has a [[InterspeciesAdoption presumably adopted squid sister Squidina]]. Sam only appears in "Klopnodian Heritage Festival" as a background character. Ironically their both existence is a {{retcon}} itself since in Season 2 episode "Something Smells", Patrick states that he has no sister.

** Bubba the caveduck also disappear in the fourth season.

* ''WesternAnimation/AllGrownUp'': Some of the characters from the original series, with one of the, being Pepper, one of Spike and Fifi's puppies, is not seen or mentioned. Only her brother, Spiffy is seen.

** Over the years, the show has had a habit of introducing characters (usually ones who are neighbors of the Smiths) who will start off as an AscendedExtra only to fall off the radar completely after about a season or two, being relegated to background cameos (if even). Notable examples of characters who've fallen victim to this over the years include Linda Memari, Chuck White and the aforementioned Hiko Yoshida.

** Foxy was a character that appeared in three ''Merrie Melodies'' shorts in 1931 before completely vanishing. His disappearance is justified, because he was a CaptainErsatz of WesternAnimation/MickeyMouse (he even provides that trope's page image), to the point that Creator/{{Disney}} [[ScrewedByTheLawyers threatened to sue]] Creator/WarnerBros after his third cartoon (he was meant to make a fourth appearance in "You Don't Know What You're Doin'!", but was replaced by Piggy, who himself disappeared after two shorts). When they came back for ''WesternAnimation/TinyToonAdventures'', like Bosko and Honey, they were also redesigned.

** The 1935 ''Merrie Melodies'' short ''I Haven't Got a Hat'' was the debut of several characters meant to become a new recurring cast, made up of WesternAnimation/PorkyPig, Beans the Cat, Kitty, Ham and Ex, and Oliver Owl. These characters subsequently became the new main characters of ''Looney Tunes'', with Beans the Cat intended to be the shorts' headlining star. However, Beans, much like his predecessor Buddy, was also met with poor reception, and by 1937 all of the characters introduced in ''I Haven't Got a Hat'' except Porky had disappeared, though Ham and Ex would make a cameo appearance in ''Film/LooneyTunesBackInAction'' nearly 70 years later.

** Jimmy Pesto last appeared in Season 11. Then, the creators discovered that his voice actor Creator/JayJohnston had an alleged role in the U.S. Capitol insurrection [[RoleEndingMisdemeanor and fired him]]. It remains to be seen what Jimmy's fate will be.

** This is a fairly common fate for several of the characters' pets, which were introduced in the first couple seasons, featured in a number of episodes and in many cases largely faded from the spotlight afterwards. The most notable examples are Applejack's dog Winona, who ceases to see any use worth the term after the third season, and Twilight's owl Owlowiscious, who remains in use for about a season longer before fading from view. The most extreme example is Princess Celestia's pet [[ThePhoenix phoenix]] Philomena, who appeared [[Recap/MyLittlePonyFriendshipIsMagicS1E22ABirdInTheHoof once]] in Season 1, was established as a rare and magical creature with a fleshed-out personality, and has never been seen or mentioned since. The only pet to stick around to the end was Fluttershy's bunny, Angel, largely because he's the only one who had consistent characterization.

** Coco "Miss" Pommel also fell victim to this trope once [[ScrewedByTheLawyers the Chanel estate sued Hasbro for likeness infringement]]. The most we hear of her after season 6's "The Saddle Row Review" is as an off-hand mention in season 7's "Honest Apple" (to provide an ugly outfit for Applejack to mock), and her sole on-screen appearance after said episode is a blink-and-you'll-miss-it cameo in the GrandFinale. Evidently, the writers figured it was easier to just not use her anymore rather than refer to her exclusively as "Miss Pommel" in future episodes. She does get at least a bit more to do in the comic.

** Patrick's Sister Sam does't appear in the spin-off series ''WesternAnimation/ThePatrickStarShow'', instead in this series, Patrick has a [[InterspeciesAdoption presumably adopted squid sister Squidina]]. Sam only appears in "Klopnodian Heritage Festival" as a background character. Ironically their both existence is a retcon itself since in Season 2 episode "Something Smells", Patrick states that he has no sister.

** Molly Collins appeared in background scenes in the first season, before disappearing halfway through the second. Eventually, it was revealed that she had been taken to a nightmarish void in reality because [[GeniusLoci the world itself]] deemed her boring and [[UnPerson erased her from existence]], only to be rescued by Gumball and Darwin. Afterwards, she made several more appearances, subverting the trope.

** Patrick's Sister Sam does't appear in the spin-off series ''WesternAnimation/ThePatrickStarShow'', instead in this series, Patrick has a [[InterspeciesAdoption presumably adopted squid sister Squidina]]. Sam only appears in "Klopnodian Heritage Festival" as a background character. Ironically their both existence is a [[retcon]] itself since in Season 2 episode "Something Smells", Patrick states that he has no sister.

** Patrick's Sister Sam does't appear in the spin-off series '''', instead in this series, Patrick has a [[InterspeciesAdoption presumably adopted squid sister Squidina]]. Sam only appears in "Klopnodian Heritage Festival" as a background character. Ironically their both existence is a [[retcon]] itself since in Season 2 episode "Something Smells", Patrick states that he has no sister.

** This might be the fate of Trixie Tang and her "friend" Veronica as of Season 9. Trixie has occasionally appeared in the background but she doesn't speak as her voice actress left and she hasn't been replaced.

** Lionel Hutz and Troy [=McClure=] were both retired after their voice actor Phil Hartman's untimely death. Since 1998, they've disappeared from ''Simpsons'' canon (with the very occasional exception of a crowd scene). Hutz's role as the Simpsons' incompetent family lawyer was taken by 'Old' Gil Gunderson. They still appear occasionally in the comics, however.

** {{Lampshade|Hanging}}d in an episode, where Rita and Runt are advertised as "Missing" [[FaceOnAMilkCarton on a milk carton]] (the "Rita and Runt" segments having been dropped in the latter half of the series' run, after which the characters themselves put in the occasional cameo appearance, but gradually disappeared - though they continued to feature in the opening credits, and were eventually restored for the direct-to-video movie ''WesternAnimation/WakkosWish'').
** Out of universe, their absence was explained because they wanted to focus on other characters.

** After the rights to were acquired by HIT Entertainment, and some of the original producers left the show, several semi-regular characters, such as Duck, Oliver, Boco and Daisy, were dropped in order to focus on the [[SpotlightStealingSquad Steam Team]]. This also happened to several one-off and recurring original characters that were made as an excuse to make and sell more toys. Season 17 and onwards, however, reinstated some of them them back into the series after Andrew Brenner took over as head writer, with Duck, Bill & Ben, and Harvey re-appearing in season 17 in prominent and respectable roles, Oliver and Toad in season 18, and Daisy and Donald & Douglas in ''Sodor's Legends of the Lost Treasure''.

** In the Seven Arts-era during the late [[UsefulNotes/LooneyTunesInTheSixties '60's]], some new characters were introduced, such as Cool Cat, Merlin the Magic Mouse and Bunny & Claude. While Cool Cat and his rival Colonel Rimfire sometimes appear in modern ''Looney Tunes'' works[[note]]specifically ''WesternAnimation/TheSylvesterAndTweetyMysteries'', ''WesternAnimation/TweetysHighFlyingAdventure'', and ''WesternAnimation/LooneyTunesCartoons''[[/note]] Merlin (and his partner Second Banana) and Bunny & Claude haven't really been seen since the Seven Arts-era. Justified, considering that the Seven Arts-era (and to a somewhat lesser extent, the [=DePatie-Freleng=] era) are widely considered the AudienceAlienatingEra of the series.

* WesternAnimation/StarvsTheForcesofEvil:

** Mermaid Man and Barnacle Boy were retired [[DiedDuringProduction after the death of]] Creator/ErnestBorgnine, who voiced the former. Their final speaking appearance was in Season 9's "Patrick-Man!" From there on out, they were only seen in images (e.g. magazines, comic books). They did return in an episode of ''WesternAnimation/ThePatrickStarShow'', albeit as babies.

** Peter's biological father was shown only once and was brought up in a few mentions.

* After the rights to ''WesternAnimation/ThomasAndFriends'' were acquired by HIT Entertainment, and some of the original producers left the show, several semi-regular characters, such as Duck, Oliver, Boco and Daisy, were dropped in order to focus on the [[SpotlightStealingSquad Steam Team]]. This also happened to several one-off and recurring original characters that were made as an excuse to make and sell more toys. Season 17 and onwards however, seems to be slowly reinstating them back into the series after Andrew Brenner took over as head writer, with Duck, Bill & Ben, and Harvey re-appearing in season 17 in prominent and respectable roles, Oliver and Toad in season 18, and Daisy and Donald & Douglas in ''Sodor's Legends of the Lost Treasure''; fans are hoping for the return of other favorite and EnsembleDarkhorse characters such as Arthur, Murdoch, Hank, Derek, Neville, Molly, and Duke.
** This trope can now be said to apply to the Logging Locos, whose main entrance way into Sodor was purportedly seen boarded up in several episodes without any explanation. WordOfGod later confirmed the tunnel wasn't boarded up, yet the Logging Locos still have yet to make a re-appearance outside a single eighteenth season cameo by Ferdinand and several learning segments, and they might as well remain gone since they were universally-panned for their one-note personalities, reckless actions, Ferdinand's grating catchphrase of "That's right!", Bash & Dash having very annoying voices and being redesigned in a way that their basis wouldn't be able to function, living on an island that is a veritable death trap, and, for many American fans, being offensive redneck stereotypes who just sit around, laugh, tell bad jokes, and see the obvious safety violations of Misty Island as "fun".