History ChuckCunninghamSyndrome / WesternAnimation

** Unwin, Sir Tuxford's page and a bully to Cavin, isn't so lucky. He disappears after Season 4.
** Unwin, Sir Tuxford's page and a bully to Cavin, disappears in the last couple seasons.
* ''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 but he doesn't really show up again, afterawards.

* ''WesternAnimation/TheFairlyOddParents'':
Any character not named Timmy and his parents, Cosmo, Wanda, Vicky, Mr. Crocker, and Jorgen (the only characters who have remained in the show from start to finish; though Vicky and Jorgen have reduced appearances throughout the later seasons) has gradually suffered this:

** 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. Similar fates had Timmy's former best friends A.J. and Chester, who in later seasons had occasional appearences with even less voice lines. Trixie's gimmick as a love interest that Timmy must win over using means other than magic [[SuspiciouslySimilarSubstitute was given to a new character]] Missy in Season 9.

** T.W. Parallini, a young parallelogram who first appeared in "[[Recap/CyberchaseS5E6TheFlyingParallinis The Flying Parallinis]]", briefly returned in the season 8 episode "The Hacker's Challenge" before disappearing altogether and isn't seen nor mentioned again after this episode. The fact that her voice actress, Creator/IsabelDeCarteret, has later retired from voice acting a few years after the episode's airing certainly doesn't help either, making it unlikely for her to come back.

* ''WesternAnimation/{{Cyberchase}}'': Widget, a younger bird stored inside Digit's chest and occasionally helps him when it is necessary, stopped appearing entirely after the season 5 episode "[=EcoHaven=] Ooze" and hasn't appeared since.

** Maya hasn't been seen or even mentioned since she got engaged to Moe in the Season 33 episode ""The Wayz We Were".

** The third season was even more confusing to Japanese viewers, because ''WesternAnimation/TransformersTheMovie'' wasn't released in Japan until 1989 (by comparison, it was released in the United States and Europe in 1986). This meant that characters who died in the movie such as Prowl and Wheeljack were alive and well in the Japanese-exclusive series.[[note]]Or they ''did'' die and were replaced by alternate selves from another universe, as described in various Japanese sources... yeah, it's complicated.[[/note]]

** Strangely enough, Melissa Duck has been seldomly used in the Looney Tunes franchise despite being Daffy Duck's significant other for several years. "VideoGame/LooneyTunesWorldOfMayhem" finally subverted this situation.

** Strangely enough, Melissa Duck has been seldomly used in the Looney Tunes franchise despite being Daffy Duck's significant other for several years. "VideoGame/LooneyTunesWorldOfMayhem finally subverted this situation.

** Strangely enough, Melissa Duck has been seldomly used in the Looney Tunes franchise despite being Daffy Duck's significant other for several years. [[VideoGame/LooneyTunesWorldOfMayhem]] finally averted this situation.

* ''WesternAnimation/BeavisAndButthead'': In the 2022 revival, many of the show's important supporting characters like Principal [=McVicker=], Coach Buzzcut, Stewart, Daria, Todd, and the Burger World are either no longer around or DemotedToExtra in Stewart's case. The only returning characters from the 90s show are David Van Driessen and Tom Anderson. However, it's otherwise justified in that Beavis and Butt-head time-traveled from 1998 to 2022 and that ''long'' 24 year time gap is lengthy enough that a lot could have changed, including those major supporting characters [[WesternAnimation/{{Daria}} moving away in Daria's case]], changing jobs, or even retiring (and/or [[UncertainDoom possibly even dying]])due to old age.

* ''WesternAnimation/BeavisAndButthead'': In the 2022 revival, many of the show's important supporting characters like Principal [=McVicker=], Coach Buzzcut, Stewart, Daria, Todd, and the Burger World are either no longer around or DemotedToExtra in Stewart's case. The only returning characters from the 90s show are David Van Driessen and Tom Anderson. However, it's otherwise justified in that Beavis and Butt-head time-traveled from 1998 to 2022 and that ''long'' 24 year time gap is lengthy enough that a lot could have changed, including those major supporting characters [[WesternAnimation/{{Daria}} moving away in Daria's case]], changing jobs, or even retiring due to old age.

** Cavin comes down with a ''nearly'' lethal case. Cavin is the main human character, meeting the Gummi Bears in "A New Beginning". The page (the first step in being a knight-in-training) to head knight Sir Tuxford, he gives the gummi's the gummi medalion his grandfather Sir Gawain gifted to him. Later, Cavin shares his role with Princess Cala as the Gummi's human confidante. Without explanation, he vanishes after being jailed in "The Crimison Advenger" midway through the second season. Cavin makes one appearance as a main character near the end of the third season ("Knights of Gummadoon"). He's again absent for several episodes, until making a full recovery in Season 4.

* ''WesternAnimation/TheLoudHouse"

** Since "WesternAnimation/The Casagrandes" have ended, The Changs haven't appeared or been mentioned since then. Sid, however, did appear in The Casagrandes movie.

* ''WesternAnimation/PollyPocket'': Main antagonists Griselle Grande and granddaughter Gwen suddenly disppeared after Season 1. It wasn't until the last episode of Season 5 that they finally came back.

* On the British animated sketch show ''Planet Sketch'' there was a character named June Spume whose gimmick was that she could transform her body parts into musical instruments and play them. She didn't return for the second season, possibly because the writers ran out of ideas for her.

* ''WesternAnimation/PostmanPat'': A few key supporting characters; Miss Hubbard, Peter Fogg, Granny Dryden, Major Forbes, George Lancaster and Sam Waldron vanished when the series was revived. In the case of Granny Dryden, it can be inferred that she [[KilledOffscreen passed away]].
** When the series was retooled as ''Special Delivery Service'', Mr. Pringle and the Pottage family also disappeared, with the former's role as the school teacher being taken by Lauren Taylor.
* On the British animated sketch show ''Planet Sketch'' there was a character named June Spume whose gimmick was that she could transform her body parts into musical instruments and play them. She didn't return for the second season, possibly because the writers ran out of ideas for her.
* In ''WesternAnimation/PuppyInMyPocketAdventuresInPocketville'', there was a supporting antagonist named Krakia, who was part of Eva's gang and was sent to the Big City to spy on Kate and Magic as they try to free Ava from the Pet Buster's [[PoundsAreAnimalPrisons prison-like pet mill]]. After the episode "The Last Piece", she does not make another appearance in the show, with her whereabouts unknown.

** Molly Collins appeared inre 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.

** Bubble Bass appeared to have suffered this fate, showing up only in the first season before disappearing completely. Apparently he was simply placed on a [[PutOnABus very long bus ride]], because he returned in the Season 8 episode "Plankton's Good Eye" before becoming an AscendedExtra in the next season.

** Mr. Krabs' mother, despite making memorable appearances in "Sailor Mouth" and "Mid-Life Crustacean" and having a major role in "Enemy In-Law", has disappeared since. She had cameos in "Spongicus" and "Lame and Fortune" and hasn't appeared since.
** [=SpongeBob=]'s grandmother disappeared from the show for no explained reason, last seen in a "Goodbye, Krabby Patty?" short. Her voice actress, Marion Ross, has since retired from acting, making it unlikely for her to come back.

* ''WesternAnimation/OzzyAndDrix'': Ozzy and Drix are the only internal 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 (justified in Mayor Phlegmming's case, since he was farted out of Frank in the final scene of the film).