Ok so like this kind of way above my level, so I'm gonna do my best with this one.
So there's stuff like Wanda can do that changes reality right? But if this were something like that, we wouldn't just remember being muppets, we'd just be muppets. Maybe stuff like people sometimes not having powers could be a Wanda thing. but not the muppet memory stuff.
I guess a really strong telepath could do memory stuff and make us remember being muppets without making us muppets, but then, why does the world keep changing right?
So like multiverse stuff makes sense, but going to other universes doesn't generally give you memories of them I don't think. Unless I guess the universe is like also a telepath or something.
But so if we've got memory stuff AND multiverse stuff that kinda seems like this thing we had a few years back called an incursion.
Basically universes kind of float around and are usually pretty far apart like pool balls but when they they get close, you can get stuff like monsters or people or buildings from another universe appearing in yours for a while or like, sometimes memory stuff like the Sesame Street stuff could be cause you and your other universe self are both you for a moment. But if it keeps happening and getting worse, sometimes the universes can full on crash into each other and everyone in both universes dies unless that can be avoided. And before you ask, idk how that can be avoided because it was like a brain trust type thing.
I mean not everyone every time though I guess, cause we had a thing here like I guess a bunch crashed into each other at the same time and Doctor Doom apparently he made this weird kind of blended world where a lot of survivors wound up. Not like several worlds' populations of everyone, but maybe a few thousand. And a bunch of Reed Richards did fix that and like, get everyoen their universes back. But that might have been a special case I think cause Doom might have also caused it to start instead of like, universes randomly crashing.