@rin.hinata03: An Incursion is one of the most terrifying concepts in Marvel's multiverse - when two universes begin colliding, eventually one or both realities can be destroyed. In the comics, this forces heroes into an impossible choice: sacrifice another universe, or watch their own universe die. That could be exactly what makes the X-Men so interesting in Avengers: Doomsday. There are rumors that their universe has already been through Incursions, forcing them to destroy other realities simply to survive. And now comes the insane theory: what if one of those realities is Tobey Maguire's Spider-Man universe? Rumors claim that an Incursion could bring the X-Men universe into collision with Tobey's world, forcing Wolverine and other mutants to enter his universe and destroy it before it destroys theirs.That would mean Spider-Man and the X-Men aren't fighting because they're enemies they're fighting because only one universe can survive. The theory even connects to the shot of Professor X watching a massive world being destroyed in the Doomsday trailer. Imagine Tobey's Spider-Man realizing that the people attacking his world aren't villains... they're heroes trying to save their own home. Spider-Man vs. the X-Men. Not because they hate each other - but because the multiverse gives them no choice. And if this is actually how Doomsday begins, Marvel is about to make the most heartbreaking crossover imaginable.