TMDb/Spider-Man: Brand New Day Movie Sadie Sink's MCU role in Spider-Man: Brand New Day sparks fan theories: Jean Grey, Mary Jane variant, or Mayday? Leaks fuel speculation. April 23, 2026 AceShowbiz - Since the announcement that Spider-Man: Brand New Day would feature Sadie Sink in a pivotal role, Marvel fans have been abuzz with speculation regarding the nature of her character.