Avengers: Doomsday | Trailer 2

Spider-Man: No Way Home's ending set up a new direction for Tom Holland's Peter Parker, but a major Avengers: Doomsday theory shows how the Marvel Cinematic Universe can walk back on that decision. After many complaints about the Multiverse Saga feeling directionless, Marvel Studios ditched Kang the Conqueror and his variants, choosing to cast Robert Downey Jr. as Doctor Doom, the franchise's new main villain. The character should appear in at least three upcoming MCU movies, with Doctor Doom reportedly set to debut in the Fantastic Four reboot before starring in Avengers: Doomsday and Avengers: Secret Wars.

Since Doom will reportedly only appear in a post-credits scene in the MCU's Fantastic Four movie, the villain's first major role in the franchise will come in Avengers: Doomsday's story. That movie will formally make him the biggest threat in the Multiverse Saga, and as such, the character will go up against many of the franchise's heroes. This includes Tom Holland's Spider-Man. However, Peter Parker should have a different reaction to meeting Doctor Doom when compared to most of the other Avengers, and a new theory shows how Spider-Man: No Way Home's ending can be affected by it.