The series, which is released weekly on Disney Plus, takes place in alternate realities spun off from the main timeline of the Marvel Cinematic Universe (MCU).
In the latest episode, Earth is ravaged by a virus that turns people – including Captain America, Iron Man and Doctor Strange – into zombies.
The episode features an appearance from Spider-Man, played in the MCU by Tom Holland, who delivers a small but crucial piece of information about his past.
A key part of Spider-Man’s origin story in the original comics is the presence of Uncle Ben, whose murder by a petty thief inspires Peter Parker to become Spider-Man.
The character’s death has featured in almost all adaptations of Spider-Man, including Sam Raimi’s Spider-Man trilogy and the Amazing Spider-Man films starring Andrew Garfield.
In the MCU, however, the story begins with Peter being raised by Aunt May (Marisa Tomei). Uncle Ben is never mentioned, leaving fans to debate whether Uncle Ben died off-screen, never existed, or was still alive somewhere in the MCU.
However, Peter Parker’s appearance in the newest What If..? appears to have put the issue to bed.
After losing Happy Hogan, Peter is asked how he remains optimistic when faced with death. “Practice, I guess,” he responds. “My mum, dad, Uncle Ben, Mr Stark… I’ve lost a lot. But my Aunt May says ‘If we don’t keep smiling when they can’t, then we might as well be gone too.’”
Spider-Man’s next full MCU outing is No Way Home, released in cinemas this December.