Marvel universes collide on a very special episode of 'WandaVision' (spoilers!)

Warning: This post contains spoilers for the fifth episode of WandaVision.

You’ve visited the Spider-verse: Welcome to the Multiverse! The 1980s-set fifth episode of WandaVision — cheekily titled “On a Very Special Episode” — officially crossed the streams between two Marvel worlds that heretofore have remained separate. In the closing moments, Westview’s most-watched citizen, Wanda Maximoff (Elizabeth Olsen), is visited by her long-dead brother, Pietro, last seen fighting, and dying, alongside the Avengers in Avengers: Age of Ultron.

Only this isn’t the Pietro that Aaron Taylor-Johnson played in Joss Whedon’s 2015 blockbuster. Instead, this Pietro is Peter Maximoff, aka Quicksilver: the version of the lightning-fast hero that Evan Peters played in X-Men: Days of Future Past and X-Men: Apocalypse, two entries in 20th Century Fox’s now-defunct X-verse. With Walt Disney’s 2019 acquisition of Fox, fans have long believed it was only a matter of time until those mutants started joining the Marvel Cinematic Universe... and that time seems to be now.

“Long lost bro gets to squeeze his stinking sister to death or what?” are the first words out of Peter’s mouth, as Wanda tries to process her sibling’s return — not to mention his new appearance — and square it with her current sitcom reality. Meanwhile, on the other side of the screen, Darcy Lewis (Kat Dennings) also tries to figure out where this “new” sibling came from. “She recast Pietro?” she asks, baffled. But Marvel-savvy audiences at home knew exactly what was going on.

It’s important to note that Wanda herself doesn’t have an X-verse counterpart. Because Pietro and Wanda — who are the offspring of mutant metal master, Magneto in Marvel comics continuity — are key players in both the X-Men and Avengers comics, Fox and Disney briefly squabbled over which universe had the rights to use them. Eventually, the two sides reached a détente where the siblings could appear as mutants in the X-verse and as Infinity Stone-augmented beings in the MCU. But the X-Men franchise ultimately chose to just feature Quicksilver, cutting a scene from Days of Future Past that would have referenced his telekinetic sister.

The barriers between previously separate Marvel universes are going to continue to collapse as Phase 4 of the MCU proceeds. It’s been rumored, for example, that Sony and Marvel’s third Spider-Man movie will feature current web-slinger, Tom Holland, meeting his predecessors, Tobey Maguire and Andrew Garfield. The actor dodged those reports in a new interview with Variety, claiming that, “If they are, they haven’t told me yet!”

But in the same conversation, he pointedly described the still-untitled sequel, which is currently in production, as “the most ambitious standalone superhero movie ever made,” lending credence to the idea that Marvel has something big up its sleeve. Speaking recently with Yahoo Entertainment, Holland’s co-star, Zendaya, seemed similarly impressed by the scope of the film. “There's a lot going on — a lot going on,” she teased.

It’s also long been known that the events of WandaVision will directly connect to the upcoming Doctor Strange sequel, tellingly titled: Doctor Strange in the Multiverse of Madness. Directed by Sam Raimi — who took over the director’s chair vacated by the original film’s helmer, Scott Derrickson — the film will team Benedict Cumberbatch’s Sorcerer Supreme up with Olsen’s Scarlet Witch. The two appeared alongside each other at Marvel’s star-studded 2019 Comic-Con panel to tease the crossover. “I’m really excited to be able to link one story on one medium and bring it into the features,” Olsen said at the time.

More recently, Olsen teased a surprise WandaVision cameo that could rival Luke Skywalker’s mind-blowing appearance on the Season 2 finale of The Mandalorian. While she could have been referring to Peters, Twitter has some other multiverse suspects they’re expecting to see before the curtain comes down on Westview.

WandaVision is currently streaming on Disney+.

Read more from Yahoo Entertainment:

• Inside the big 'WandaVision' reveal: 'Episode 4 was always meant to be a reset'

• The game-changing 'WandaVision' Episode 4 answers questions and reveals secrets

• 'WandaVision': What you need to know about the bonkers ending of the Marvel show's third episode