Warning - This article contains spoilers for The Marvels.
The leading heroine is seen lying down in a hospital bed and suddenly a Variant of her mother Maria Rambeau appears. Severely confused, the big cameo then comes into play with Beast, a notable member of the X-Men, joining the fray and trying to understand how Monica got into this new parallel reality:
"All we know is that Binary found you. My theory? You somehow crossed through a tear in space-time. You are now in a reality parallel to your own. Which, of course, is impossible."
Before leaving the Rambeau pair, Beast remarks "Charles asked for an update," confirming that Charles Xavier aka Professor X has an active role in superhuman affairs in this new universe.
Who is Beast in The Marvels Post-Credits Scene?
"Confusion is but the first step on the journey to knowledge" - Beast
The version of Beast seen in The Marvels' post-credits seems to be voiced by the original X-Men actor Kelsey Grammer. However, this version of the massive blue mutant is fully CGI, moving away from the practical makeup from the Fox films.
Hank McCoy is a leading member of the X-Men and was portrayed by Grammer and Nicholas Hoult previously in live-action. This is the second time that a legendary X-Men character has appeared in the MCU, with the first being Patrick Stewart's Charles Xavier aka Professor X in a cameo from Doctor Strange in the Multiverse of Madness.
Interestingly, the common thread between the two cameos was that each member of the X-Men was accompanied by a version of Maria Rambeau. In Multiverse of Madness, it's on Earth-838, but it's not explicitly stated which timeline is visited in The Marvels.
What Universe is The Marvels' Post-Credits Scene In?
One notable difference between the alternate universe at the end of The Marvels and Earth-838 is that Maria is not Captain Marvel but the hero Binary from Marvel Comics.
In the comics, Binary is an alter-ego of Captain Marvel she took on after she underwent an evolutionary experiment by the Brood, which triggered her latent powers. During this same time in the comics, prior to becoming Binary, Carol had been associated with the X-Men.
This unique take has Maria filling the shoes of Binary, which seemingly rules out this being the same version from Multiverse of Madness.
In the parallel reality where Monica traps herself, it appears that the X-Men are well-established, with Binary possibly being a member. Not only is a giant "X" displayed on a wall (looks like a door opening) but Hank specifically says that "Charles wants an update," indicating that Professor X is alive and well in this universe.
Considering the return of Kelsey Grammer, this makes the odds of other similar faces also being present in this reality, possibly making it an alternate version of what was seen in the Fox films.
More specifically, the utopian timeline created at the end of X-Men: Days of Future Past could be what is seen at the end of The Marvels. Grammer's Beast was also featured in this reality, possibly indicating a connection.
A more far-fetched theory is that this is the same universe seen in X-Men: The Animated Series, soon to be revitalized by Marvel Studios with X-Men '97.
The main reasoning for this idea is that Beast is fully CGI in The Marvels, giving him much more of an animated look similar to what's seen in the series. Considering X-Men '97 is an official Marvel Studios project, there is an opportunity to overlap some of animation with live-action, similar to characters in What If...?.
Regardless of what branched timeline this is, Monica is stuck there, indicating that this won't be the last time it's featured. This universe could be pulled into the fray during the events of future projects like Deadpool 3 or Avengers: The Kang Dynasty.
How The Marvels Sets Up the X-Men
The MCU's worst-kept secret is that the X-Men will soon be entering the fold in a major way. It was reported that Disney is planning to arrange writer meetings to discuss pitches for the first new X-Men movie to be produced by Marvel Studios.
Within the Multiverse Saga, it's becoming more evident that Marvel is planning on bringing back several former X-Men actors before potentially recasting a younger crew.
Similar to Earth-838 Professor X and the newly discovered parallel reality Beast, this is an indication that different Variants of the original X-Men will continue to appear.
Considering Beast, Professor X, and many more X-Men are likely in the universe that Monica is trapped in, perhaps this is how they are brought into the MCU. Even if it's not a permanent stay, it's likely that this group will become aware of Earth-616's (or Earth-199999's) existence.
Avengers: Secret Wars is set to complete the Multiverse Saga and end Phase 6. This could ultimately be used as a tool to bid farewell to previous actors who played the X-Men for good and then begin again in Phase 7 with a fully recast team.
The Marvels is playing in theaters beginning Friday, November 10.