A new fan theory regarding Spider-Man 4’s villain could bring about an exciting MCU debut.

Marvel Studios and Sony Pictures’ Spider-Man 4, also known as Spider-Man: Brand New Day, is now in production. Directed by Shang-Chi and the Legend of the Ten Rings’ Destin Daniel Cretton, the superhero blockbuster film will once again see Tom Holland reprise his role as Peter Parker/Spider-Man.

So far, there’s been no word regarding who the main antagonist of Spider-Man 4 will be. It has been confirmed that Michael Mando will be returning as Mac Gargan/Scorpion, with Brand New Day being the character’s first MCU appearance since Spider-Man: Homecoming, though he’s not expected to be the central villain.

What villain could debut in Spider-Man 4?

Earlier this month, a viral Twitter post showcased a “moodboard,” created by costume prop modeler Monica Avitto, for the film’s villain.

While many thought this moodboard could be alluding to Silver Samurai, a new theory that’s becoming popular on social media, as shared by @DrawsTom, suggests Spider-Man 4’s villain could actually be Alistair Smythe, also known as Spider-Slayer.

Scooper Daniel Richtman even noted that this is a “great” theory, though this does not mean Spider-Slayer will definitely be in the movie, as this has not been confirmed by Marvel or Sony at this time.

Created by Louise Simonson and Mary Wilshire, Alistair Smythe first appeared in 1985’s The Amazing Spider-Man Annual #19. Gifted when it comes to his knowledge of robotics, Alistair inherited his Spider-Slayer legacy from his father and typically operates a bioorganic carapace after becoming paralyzed from the waist down. The character was voiced by Maxwell Caulfield in Spider-Man: The Animated Series and also briefly appeared in 2014’s The Amazing Spider-Man 2, where he was portrayed by B. J. Novak.

Spider-Man 4 will be released in United States theaters on July 31, 2026, as part of Phase 6 of the MCU.