John Krasinski's Reed Richards name-dropped "Incursion" in Doctor Strange in the Multiverse of Madness—the precursors to the end of the Multiverse. But, how Incursions occur differs significantly from the comics, which has led to the popular theory that it's a plan by Marvel Studios President Kevin Feige to destroy Morbius' universe.
For years, Sony has been attempting to crowbar its way into the Marvel Cinematic Universe with little success until Spider-Man: No Way Home. In one of the post-credits scenes, it's revealed that Tom Hardy's Eddie Brock and Venom did make the jump to the MCU, but only briefly before immediately getting sucked back to their universe.
Seemingly unsatisfied with only being part of the Multiverse in the MCU, the post-credits scene for Morbius showed Michael Keaton's Vulture being ripped from the MCU and transported into Sony's Spider-Man Universe. However, this blatantly desperate move from Sony to bolster the credibility of its cinematic universe could spell the end for it instead.
What Causes Incursions?
In the comics leading up to the event, "Secret Wars," Incursions began to happen due to a contradiction in the timeline of the Multiverse, resulting in two universes colliding with each universe's respective Earth as the epicenter. Both Earths would then collide with one another, and if they made contact, both universes would be obliterated.
It would continue until only two Earths remained, ending with either one Earth in the Multiverse left standing or none at all. Otherwise, travel between Multiverses in the comics poses no dangers whatsoever, but that isn't the case in the MCU.
When Benedict Cumberbatch's Doctor Strange of Earth-616 is brought before the Illuminati, Mr. Fantastic tells Strange, "your arrival here confuses and destabilizes reality. The larger the footprint you leave behind, the greater the risk of an Incursion."
Richards further explains that an Incursion happens "when the boundary between two universes erodes and they collide, destroying one or both entirely."
This explanation suggests that the arrival of Strange and America Chavez itself could risk triggering an Incursion between Earth-838 and Earth-616. However, this would pose a significant problem for Sony, which just had Vulture yanked from Earth-616 and placed into the SSU, presumably for the foreseeable future.
Going by the explanation of Incursions established in Multiverse of Madness, the longer Vulture stays in that universe, the higher the chance of an Incursion happening. Adrian Toomes' very existence would theoretically pit Sony's unnumbered Earth against Earth-616 in an inevitable showdown.
Fight For Survival
The crux of Incursions in the comics was that the only way to save both universes was for one Earth from either universe to be destroyed before they collide. The superheroes had the moral dilemma of either having to kill an entire planet of billions to save trillions or letting both universes die.
It's unsure how or if Incursions can be purposefully avoided by one universe in the MCU or that it's left to chance, but as Mr. Fantastic stated, it's either "one or both" universes that are destroyed. Not to mention that Charlize Theron's Clea suggested to Strange that the Incursion he caused could be prevented or mitigated, so Marvel Studios undoubtedly has some solution in mind for the Incursion conundrum.
So, if Incursions follow the rules of the comics, how would one imagine a fight between Sony's universe and Earth-616 going? It's safe to say that the odds are probably in favor of the universe with several dozen superheroes capable of leveling whole cities over the one that has Jared Leto in it.
Of course, Sony could ignore the post-credits scene from Morbius and pretend it didn't happen, thus dispelling any notion that its universe is at any risk of being destroyed. But not even that wouldn't help save it, as Sony's universe would still be at the mercy of Kevin Feige due to it now officially being part of the MCU Multiverse.
In the comics, the last two universes in the Multiverse were Earth-616 and Earth-1610, which both proceeded to fight to protect their respective Earths. A confrontation similar to this has likely been seeded already in the MCU with the introduction of Earth-838, a universe that now has justifiable reasons for not being merciful towards Earth-616, especially now that the Mordo of Earth-838 will lead the Illuminati.
So, where does that leave Sony's universe? Well, if the MCU follows at least the basic concept of "Secret Wars," then Sony's universe will be wiped from existence no matter what the studio does. After all, Marvel Studios has the final call regarding the Multiverse and which universes will survive.
The Morbius Universe Losing (Even More) Credibility
Of course, just because there's a real possibility of Marvel Studios destroying the Multiverse, which now includes the SSU, doesn't mean that Sony will literally be forced to stop making Spider-Man spin-offs—that'd be silly. It would, however, do a number on the already poor credibility of the SSU and its connection to the MCU.
For example, if Vulture sticks around for Sony's spin-offs, it weakens the idea of the SSU being affected by Incursions. On the other hand, if Sony did backpedal on the post-credits scene, it would only be a temporary fix and look quite embarrassing on Sony's part, leading to the next problem.
It's evident at this point that outside of collaborating on Spider-Man movies, Marvel Studios and Sony don't communicate each other's plans entirely – or just don't listen to one another. Due to this poor communication, it'd be unsurprising if Marvel Studios wasn't fully prepared for Sony to pull Vulture out of the MCU suddenly. At the same time, Sony probably wasn't told anything about how the Multiverse works in the MCU.
When Marvel Studios adapts "Secret Wars," it will be curious how Sony will respond if the SSU is indirectly destroyed. Do they ignore it? Will they try shoving in another plot point related to the Multiverse, perhaps by explaining briefly that their universe was recreated after the events of this hypothetical adaptation of "Secret Wars"?
Regardless, Feige has the power to make Sony's cinematic universe feel even more detached from the MCU than it already has been. It all depends on how Sony reacts and if Marvel Studios will give them a life raft or not.