A teenage X-Man who does not want to be there, does not want to talk to you, and can level a building.
Negasonic Teenage Warhead is a young mutant who can generate atomic bursts around her body, and a member of the X-Men. She spends most of her first film refusing to look up from her phone, which is a joke that works because Colossus keeps trying to make her care.
She matters here for a reason that has nothing to do with the fighting. She and Yukio are together across two films, treated as ordinary and never explained, which was not common in a superhero film of that size in 2018.
Show detailsWhere the name comes from
It is taken from a Monster Magnet song, and the films know it is absurd. The character in the comics is a different person with different powers, and the film versions keep only the name and the attitude.