While astrophysicist Erik Selvig—who made his first appearance in the Marvel Cinematic Universe in 2011’s Thor, and is played by Stellan Skarsgård—is nowhere near the most influential character in the wide-ranging superhero world, a new fan theory has some people believing that he could potentially be the key to defeating Thanos in the highly anticipated (and still-untitled) Avengers 4.

According to ComicBook.com, the theory—which was posted on the Marvel Studios subreddit on Tuesday—could be the most thorough fan argument yet.

While Selvig hasn’t popped up in quite some time (since 2015's Avengers: Age of Ultron to be exact), the theory suggests that as he has predicted several events in the MCU before, he also knows about the deadly snap, which tragically killed off half the universe—taking the lives of many of our favorite characters along the way.

The theory suggests that Selvig’s notes from Thor: The Dark World (2013) can be deciphered into hinting at travel through both time and space. Not only would this make sense as to how the snap could be reversed, but it also would implement the most popular theory, which states that time travel will be used in Avengers 4.

According to the Redditor, Selvig not only knew that The Snap would happen, he also predicted that the larger-than-life Cosmic entities will actually be bigger threats than Thanos in the upcoming fourth Avengers film.

The last prediction from the theory is that Thanos will feel guilty about murdering his daughter, Gamora, and attempt snapping again to reverse the action, which would only create a larger rip in the space-time continuum. Only an astrophysicist would know what to do—one who, conveniently, was just confirmed to have survived Avengers: Infinity War.