Perhaps the craziest fan theory to come out of Avengers: Infinity War has to do with a reinterpretation of the ending, one that would be a real game-changer for Avengers 4. The theory would change the entire universe, literally, because it would mean that everyone who died didn’t actually die; they were just transported into an alternate reality.

Huge spoilers follow for Avengers: Infinity War but, strangely, also for The Leftovers and Lost.

Avengers: Infinity War hit theaters on April 27, and everyone’s reeling from the emotional aftermath after Thanos erased half the universe’s population from existence. Perhaps out of grief and denial, tons of fans refuse to accept that the likes of Peter Parker, T’Challa, and Doctor Stephen Strange are indeed dead. Doctor Strange certainly made it seem like he had some grand plan that involved letting Thanos succeed in his mission, and this new theory posits that his snap with the Gauntlet didn’t kill half the universe. It instead split the universe into two separate realities.

Perhaps the earliest version of the theory popped up on Saturday on a subreddit devoted to the idea that Thanos was right.

This version assumes that Thanos’s snap made another Big Bang that created a parallel universe for the other 50 percent of people who turned to ash in the movie. Infinity War did make a point to highlight that the Infinity Stones were created during the first Big Bang. This would make the ending to Infinity War a lot like what happened during the event from The Leftovers or throughout later seasons of Lost.

Thanos’s intention wasn’t necessarily about killing for psychopathic reasons. He seemed to legitimately believe he was doing the universe a favor by eliminating half the population. Maybe the full Infinity Gauntlet split the universe into two halves rather than kill all those people because Thanos was more interested in population control than mass murder?

A far more thorough unpacking of the same theory came on Sunday.

Redditor datageek9 thinks Marvel will go for “a more pseudoscientific/technology based resolution” because Thanos split reality into two, and everyone who died in Universe A actually watched the other half die in Universe B. In this theory, Tony Stark’s survival is important for Universe A to find a technological solution to this problem. That could also be part of the reason why Ant-Man and the Wasp is the next MCU movie coming out. That movie could have technological implications that’ll help the Avengers re-merge the universes. “The quest for the Avengers is now to find a way to “tunnel” from one universe to the other, and join them back together,” datageek9 writes, assuming the solution might combine the Quantum Realm with Tony’s BARF technology.

If Avengers 4 does utilize some kind of universe-altering shenanigans, then chances are it might involve alternate realities in some fashion. Could the Marvel Cinematic Universe we’ve spent a decade on end and these movies continue on in a rebooted alternate reality? How might Captain Marvel factor into it somehow?

We’ll see just how much we learn about the Quantum Realm when Ant-Man and the Wasp hits theaters on July 6, 2018.