Chadwick Boseman's Final Performance as Black Panther Teased in 'What If...?' Trailer

Long a staple of the Marvel Comics print universe, and something that's just beginning to be fully explored in the Marvel Cinematic Universe, alternate realities fully take center stage in the upcoming animated anthology series, "What If...?"

Based on various comic series of the same name, each chapter takes a look at different points in Marvel history and asks "what if" this had happened instead of that. It's a simple enough premise that has captured generations of imaginations and spawned hundreds of stories.

It also, tragically and unexpectedly, became the home of Chadwick Boseman's final performance as King T'Challa, ruler of the African nation of Wakanda. Only, in this "what if" scenario, T'Challa did not immediately step up to become king, rather taking the place of Peter Quill in a reimagined "Guardians of the Galaxy."

While an unexpected twist for the character, and the actor, his inclusion in the first trailer for the Disney+ series proved surprisingly moving. This may not be the beloved T'Challa who made a billion dollars at the box office, but that familiar voice and cadence prove it's not far off, either.

With "Black Panther: Wakanda Forever" having reportedly begun filming, kicking off what will be the next chapter of the "Black Panther" saga without Boseman, it was especially poignant to hear his regal voice one last time, knowing that there is one more performance to look forward to.

Even beyond T'Challa's unexpected rogue turn, there were plenty of other twists to enjoy in this trailer, including what appeared to be a first MCU appearance for those dastardly and dangerous "Marvel Zombies," and a more heroic role for the popular Agent Carter character, as Captain Carter.

There's that iconic shot of the Avengers assembling for the first time in New York, only suddenly it's the Guardians of the Galaxy (New York might be in trouble), and Loki leading an army.

While Chris Evans and Robert Downey, Jr. did not step in to do the voice work for Captain American and Iron Man (the latter rather obvious in this clip), plenty of other MCU stars did return, including a hilarious comment from Chris Hemsworth's Thor in the trailer.

Other MCU stars who lent their efforts to "What If...?" include Hayley Atwell (Agent Carter), Mark Ruffalo (Bruce Banner), Jeremy Renner (Hawkeye), Sebastian Stan (Winter Soldier), Tom Hiddleston (Loki), Michael B. Jordan (Killmonger), Paul Rudd (Ant-Man), Josh Brolin (Thanos), Natalie Portman (Jane Foster), Karen Gillan (Nebula), Michael Rooker (Yondu), Michael Douglas (Hank Pym), and Jeff Goldblum (Grandmaster). Jeffrey Wright joins as the Watcher, the enigmatic, celestial being who oversees all of these alternate possibilities.

Seth Green gives voice to Marvel's wackiest movie star, Howard the Duck, who's only existed as a cameo appearance in the MCU to this point.

"What If...? kicks off a first season of 10 episodes August 11 on Disney+. The series has already been renewed for a second season.