A crossover that takes place in a multiverse ala Kingdom Hearts.
The concept for The Multiverse sure is amazing. The idea of different dimensions, each representing a different idea being used. It'd be great if someone were to visit them. Okay, let's do just that! But how about we spice this up by having each dimension be the world of an entire work? This is pretty much how a Multiverse Crossover works. This is a kind of crossover that's been done rarely in non-fan works, for obvious reasons. It entails that each world within the Multiverse is actually a world a certain work exists in. A main character, mostly an Original Character, travels throughout these worlds and crosses over into that work. Kind of like a Massive Multiplayer Crossover, only one work is getting the spotlight at a time. Basically all the worlds are in separate Alternate Dimensions or Alternate Universes inside a bigger multiverse. Not to be confused with a Crisis Crossover. A subtrope of Massive Multiplayer Cross Over. See also Intercontinuity Crossover and Mega Crossover. Needs a Better Description. Is it Too Rare to Trope?