Of all the announced Marvel Cinematic Universe Disney+ series, What If...? remains most enigmatic. Relatively little is known about the animated anthology, which explore what might have happened if events of the MCU had played out differently. Narrated by Jeffrey Wright as The Watcher, will debut with an episode depicting a world in which Peggy Carter, and not Steve Rogers, was given the Super-Soldier Serum. However, a closer inspection of the series' logo provides another clue about what to expect.

By zooming in on the "W," eagle-eyed fans discovered an Easter Egg of sorts: a zombified Captain America, suggesting that What If...? will somehow integrate elements of a long-running Marvel Comics metaseries.

While some have suggested the figure might be Captain America's iconic foe the Red Skull, it's more likely an animated take on Marvel Zombies.

What is What If...?

Originally published from 1977 to 1984, the original What If...? comic was premised on Uatu The Watcher observing events of the mainstream Marvel Universe, and then introducing a key moment -- a point of divergence -- in which everything might have changed. Scenarios included "What if Gwen Stacy Had Lived?" and "What if Spider-Man Had Joined the Fantastic Four?"

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The series was revived from July 1989 to November 1998, with perhaps the most noteworthy introducing Mayday Parker, otherwise known as Spider-Girl. The title has been resurrected several more times since then, as limited series and one-shots.

What About Marvel Zombies?

Marvel Zombies began in 2005 with Ultimate Fantastic Four, in which that reality's Reed Richards came into contact with an alternate universe version of himself. In that world, a zombie apocalypse had turned every superhero into a flesh-eating undead fiend.

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Since then, Marvel Zombies has taken on a life of its own, with multiple miniseries further exploring the mash-up of horror and superheroes; it's even crossed over with The Evil Dead franchise, in which Ash Williams stumbled into the Marvel Zombies Universe just as the plague starts to spread.

Unsurprisingly, Marvel Comics just announced at Comic-Con International that it will return to Marvel Zombies this fall.

It's highly possible that the Marvel Zombies multiverse will explored in What If...? After all, the property recently influenced a nightmarish illusion in Spider-Man: Far From Home in which Mysterio creates a zombie-Iron Man illusion. So, while Marvel Zombies isn't exactly MCU canon, it's pretty close.