History ChuckCunninghamSyndrome / MarvelUniverse

* ''ComicBook/CombatKellyAndHisDeadlyDozen'': Emory 'Snake-Eye' Simpson never appears after the first issue.

* Creator/MarkWaid's final arc of ''ComicBook/{{Champions|2016}}'' saw ComicBook/{{Ironheart}}, Red Locust and the new [[ComicBook/TheUnstoppableWasp Wasp]], Patriot and Falcon join the team. While Ironheart and Wasp remained when Jim Zub took over the series, Falcon, Red Locust and Patriot all vanished without explanation.

* When Creator/BrianMichaelBendis left ''ComicBook/{{Daredevil}}'', the titular character had been imprisoned in one cell block with Kingpin, Owl and Jigsaw. New writer Ed Brubaker removed Jigsaw, without any explanation.
* Often happens to Franchise/SpiderMan' supporting cast after all bigger changes of status quo. High school classmates from his early years, college classmates and associates, co-workers from the Daily Bugle, associates from various other occupations, and some of his love interests, vanish without explanation and are rarely mentioned afterwards. A decent example is Joy Mercado, a female reporter who was depicted as one of Peter Parker's closest associates from 1985 to 1993. She made a few cameos in the rest of the 1990s, as the Daily Bugle was de-emphasized at the time, and has since vanished without a trace.

** His whereabouts would finally be revealed almost 60 years later, in 2021's ''The Marvels''.

* Kasper's teammate, Josiah X, also pretty much vanished into thin air. Ditto for Josiah's nephew Eli Bradley aka The Patriot from ''ComicBook/YoungAvengers'', who hasn't been seen since ''ComicBook/AvengersTheChildrensCrusade''.

** Marvel Boy ([[IHaveManynames formerly the Protector]]) had a girlfriend named Annie while he was a member of the Avengers. They had a very close relationship, and there were even some [[LeftHanging dangling plot threads]] concerning their relationship when [[Creator/BrianMichaelBendis Bendis]] left the book. Then came the second volume of ''Young Avengers'', where Marvel Boy was shown shacking up with Kate Bishop without even a single mention of Annie.
** This was eventually explained. Marvel Boy dumped Annie at some point between ''The Avengers'' and ''Young Avengers'', eventually leading to her [[spoiler:apparent]] return as an AxCrazy WomanScorned.
* Echo, ComicBook/{{Daredevil}}'s former LoveInterest, was once a member of the ComicBook/NewAvengers briefly before disappearing, then briefly reappearing in ''ComicBook/SecretInvasion'', then disappearing again. This wasn't lost on writer Creator/BrianMichaelBendis, who had Spider-Man question where she was at one point and have her flip her shit at ComicBook/LukeCage and ComicBook/JessicaJones when she was poked to be Danielle Cage's babysitter.

** Echo has recently turned up in Ta-Nehesi Coates' ''ComicBook/CaptainAmerica'' run as one of Sharon Carter's "Daughters of Liberty" team. Which is interesting, since Bendis had killed her off WHILE explaining where she'd disappeared to in his Moon Knight run. (Undercover trying to bring down the Count Nefaria mob.)

* Kasper Cole became the new ''ComicBook/BlackPanther'' in the last year or so of Creator/{{Christopher Priest|Comics}}'s run and then starred in the short-lived SpinOff, ''The Crew'', before completely vanishing off the face of the Earth. (A decade and a half later, he briefly reappeared in Ta-Nehisi Coates' run).

* Doctor Strange was a surprisingly effective bad guy. He easily defeated ComicBook/IronMan and made a successful getaway when his too-honest daughter freed the hero. And he was never seen again! The name was later applied to Creator/SteveDitko's [[ComicBook/DoctorStrange unrelated magician]]. An explanation of what happened to him is long overdue by Marvel.

* Kasper's teammate, Josiah X, also pretty much vanished into thin air. Ditto for Josiah's nephew Eli Bradley aka The Patriot from ''ComicBook/YoungAvengers'', who hasn't been seen since ''ComicBook/TheChildrensCrusade''.

* When the ComicBook/{{Micronauts}} began appearing starting in 1996 issues of ''ComicBook/{{Cable}}'', not only was their reappearance due to a very apparent {{retcon}}, but no mention was made of Acroyear or Huntarr. Acroyear's absence is most likely due to the fact that Marvel no longer has the rights to any of the Micronaut characters derived from the old-school toyline. It doesn't explain why Huntarr is not there, as he was created by Marvel writer Creator/BillMantlo.

* Creator/MarkWaid's final arc of ''ComicBook/{{Champions|2016}}'' saw ComicBook/{{Ironheart}}, Red Locust and the new [[ComicBook/UnstoppableWasp Wasp]], Patriot and Falcon join the team. While Ironheart and Wasp remained when Jim Zub took over the series, Falcon, Red Locust and Patriot all vanished without explanation.

** Echo has recently turned up in Ta-Nehesi Coates' ''ComicBook/CaptainAmerica'' run as one of Sharon Carter's "Daughters of Liberty" team. Which is interesting, since Bendis had killed her off WHILE explaining where she had disappeared to in his Moon Knight run. (Undercover trying to bring down the Count Nefaria mob.)

** Echo has recently turned up in Ta-Nehesi Coates' ''ComicBook/CaptainAmerica'' run as one of Sharon Carter's "Daughters of Liberty" team. Which is interesting, since Bendis had killed her off WHILE explaining where she'd disappeared to in his Moon Knight run. (Undercover trying to bring down the Count Nefaria mob.)

** Kala, Queen of the Netherworld was one of Iron Man's earliest foes. She has appeared sporadically since this, but her rapid aging when leaving her realm limits her appearances to situations where she's forced out of it by Subterranean politics, most recently (to my knowledge) during the Subterranean Wars in the 1990s.

* Surprisingly effective bad guy Doctor Strange easily defeated ComicBook/IronMan and made a successful getaway when his too-honest daughter freed the hero. And he was never seen again! The name was later applied to Creator/SteveDitko's [[ComicBook/DoctorStrange unrelated magician]]. An explanation of what happened to him is long overdue by Marvel.