Brianna Caitlin Hildebrand is an American actress. She is best known for appearing as Negasonic Teenage Warhead in the films Deadpool (2016), Deadpool 2 (2018), and Deadpool & Wolverine (2024). She is also known for appearing in the web series Annie Undocumented, and as the character Aurora in the Netflix show Lucifer. She also portrayed Elodie Davis in the show Trinkets.

Negasonic Teenage Warhead is a superheroine appearing in American comic books published by Marvel Comics. Created by Grant Morrison and Frank Quitely, the character first appeared in New X-Men #115 (2001). She is named after the song "Negasonic Teenage Warhead" by Monster Magnet. She belongs to a subspecies of humans called mutants, who are born with superhuman abilities. Negasonic Teenage Warhead's appearance and powers were eventually altered in the comics to match her appearance in the Deadpool films, in which she is portrayed by Brianna Hildebrand.