Ellie Phimister, better known for as Negasonic Teenage Warhead, is a fictional character of Marvel'sX-Men. Ellie was a Genoshan teenager and a student of Emma Frost. Her mutant power gave her precognitive nightmares and premonitions. She was close the codename "Negasonic Teenage Warhead" for herself, and close friend/teammate of Deadpool and Colossus.