Why Sadie Sink's Character Got So Much More Powerful At The End Of Spider-Man: Brand New Day

Published Aug 5, 2026, 9:00 AM EDT Richard Craig is a Senior Author at Screen Rant covering film and TV. Richard has also written extensively about horror and film soundtracks, contributing a chapter to the first major academic collection on the folk horror genre, The Routledge Companion to Folk Horror. Richard is also a performing musician and holds an MA in Music and Sound Art. Sign in to your ScreenRant account Spoiler alert! This article contains major spoilers for Spider-Man: Brand New Day. One of the biggest surprises in Spider-Man: Brand New Day is just how dramatically Jean Grey's powers evolve over the course of the movie. When audiences first meet Sadie Sink's version of Marvel’s iconic X-Men character, she is already incredibly dangerous. Her telepathic abilities allow her to read minds, influence people, and gather information in ways that make her one of the most formidable individuals Spider-Man has ever encountered. However, by the film's final act, Jean has become something else entirely. Marvel's Spider-Man: Brand New Day reveals that Jean's powers are continuing to develop, with several characters noting that her mutation appears unusually unstable. While much of the story focuses on Spider-Man's own evolving spider mutations, Jean is undergoing an equally significant transformation. The change becomes impossible to ignore once her abilities begin expanding beyond simple telepathy. By the climax, Jean is capable of exerting psychic control over huge numbers of people simultaneously. During the final confrontation, she seizes psionic control of everyone within a mile of her location, turning an already dangerous situation into a full-scale crisis. Even more alarming is the fact that her telepathic growth is accompanied by entirely new abilities. Rather than being a random upgrade designed to make the finale more spectacular, Jean's further mutation can be canonically explained. Learning Of Sara's Death Kick-Started A Second Mutation In Jean In X-Men lore, mutations are triggered by intense personal trauma. After learning about her sister Sara's murder, Jean experiences an emotional shock severe enough to trigger what effectively becomes a second stage in her mutation. Following the revelation, her telepathy grows significantly more powerful than it was earlier in the story. Perhaps even more importantly, Jean develops powers she did not previously possess. Damage Control scientists specifically note that she is suddenly showing signs of telekinesis, a classic Jean Grey power not yet depicted in Brand New Day. The combination dramatically changes the threat Jean represents. Earlier in the film, she primarily influences minds. By the finale, she can manipulate both minds and the physical world around her. It is a version of Jean Grey whose powers are evolving faster than anyone can understand, including the scientists attempting to study her. How Does Jean's MCU Origin Compare To The Comics? In the comics, Jean's powers first emerge after the death of a childhood friend. Witnessing the tragedy triggers the mental abilities that would eventually make her one of the most powerful mutants in Marvel history. The experience has a lasting impact on her development and helps define her relationship with her powers. The MCU adaptation follows a similar structure but replaces that event with something far more personal. Rather than a childhood friend, it is the death of Jean's sister Sara that triggers the explosive growth of her mutation. The change arguably creates a stronger emotional foundation for the character. While the loss of a friend is undeniably traumatic, the death of a sibling carries an even deeper personal connection. That makes Jean's reaction easier to understand and gives greater emotional weight to the dramatic expansion of her powers. It also helps explain why the revelation affects her so profoundly that it appears to unlock an entirely new stage of her mutation in Spider-Man: Brand New Day.