The ending of The Marvels left Monica Rambeau in shambles. What followed got even crazier.
“Who are you?”
Warning: Major soilers ahead for The Marvels
Monica (Teyonah Parris) sacrifices herself to close the time ripple in space. Carol (Brie Larson) and Kamala (Iman Vellani) give her enough energy from their powers to be able to close it. Unfortunately, this results in her being lost on the other side in another dimension.
She knew this all along, though, as she tells Carol that she “always knew” she'd have to stay back. Carol is heartbroken, and moves into her mom's Louisiana house.
In the mid-credits scene, Monica wakes up in a hospital. She's greeted by her mom, Maria (Lashana Lynch), or so she thought. Pretty quickly, Monica realizes that this isn't her mom, as Maria does not recognize her, meaning she is in a different universe.
When she turns her head, she sees Beast from the X-Men. The blue mutant is in a lab coat. “You are now in a reality parallel to your known,” he says, adding, “which is, of course, impossible.”
As Maria stands up, her blanket comes off and reveals a red and white suit that resembles the Binary suit from the comics. Beast also references Charles Xavier, claiming he asked for an update.

This isn't the first time Lynch has played an alternate version of her character. In one sequence in Doctor Strange in the Multiverse of Madness, she plays Captain Marvel. Her and the other variants, including John Krasinski's Reed Richards, are taken out by Wanda.
Where this leaves the MCU is unclear. Carol and Nick Fury (Samuel L. Jackson) seem to retain hope that Monica is alive. Perhaps they will all reunite later down the line with the X-Men in tow. It appears those teaser trailers that seemed to tease the X-Men were true after all.
The Marvels is in theaters now.