Shocking 'WandaVision' Reveal May Be One Of The Biggest Moments In MCU History

X-Men, assemble?

In addition to wild reveals, aging twins and dead dogs, the overloaded fifth episode of “WandaVision” may have just dropped one of the biggest moments in the Marvel Cinematic Universe: the arrival of mutants.

In the waning moments of the episode, Vision (Paul Bettany) finally catches on that he’s in a fake reality and argues with Wanda (Elizabeth Olsen), who claims she’s not actually behind everything in the sitcom world. But the pair are interrupted by a ring at the door.

Wanda goes to answer, and the camera reveals none other than Wanda’s supposedly dead brother, Pietro. But it’s not Aaron Taylor-Johnson, who played Pietro/Quicksilver in “Avengers: Age of Ultron.” It’s Evan Peters, aka the Quicksilver from Fox’s “X-Men” movies.

What!?

Darcy (Kat Dennings), who is watching what is happening onscreen from outside the alternate reality/anomaly, thinks Wanda has “recast” Pietro. So it’s clear Peters is a different version of Quicksilver, not just an actor change we’re supposed to go along with, like when Marvel swapped out Terrence Howard for Don Cheadle as War Machine.

With that shocking moment, it seems mutants and the “X-Men” characters, which were previously ignored in Marvel movies over rights issues, have seemingly arrived in the MCU.

And us non-mutants were not ready.

Now, it seems like we have X-Men, but that doesn’t mean these multiverse/franchise crossover shenanigans are official. It could be a big fake-out.

No one in “WandaVision” is exactly what they seem, and we don’t know that Peters’ Quicksilver is either. He could just be a resident of the town playing Wanda’s bro.

Additionally, Marvel boss Kevin Feige reportedly said just a couple of years ago that introducing the X-Men was not in Marvel’s five-year plan.

But, as everyone who has been stuck in quarantine for months knows, plans change. And if you’re ever going to introduce the X-Men, “WandaVision” seems like the perfect opportunity to do so.

In Marvel’s “House of M” comic, an inspiration for “WandaVision” that also has Wanda creating an alternate reality, the story ends with Wanda getting rid of mutants. One of the most popular theories going around is that “WandaVision” will end in the opposite way, with her bringing them in.

Yes, this could be one of the biggest moments in the MCU. Or, with a few episodes of “WandaVision” still to go, it could be a red herring.

Whatever the case, we’re X-cited.

This article originally appeared on HuffPost and has been updated.