Jennifer Walters, the cousin of Bruce Banner (the Hulk), is the small and somewhat shy daughter of Los Angeles County Sheriff William Morris Walters and Elaine (née Banner) Walters (who died in a car crash when Jennifer was 17). Operatives of Nicholas Trask, a crime boss who had crossed paths with her father, shot and seriously wounded her on the day that Banner visited her to tell her about his transformation into the Hulk. Since no other donors with her blood type were available, Banner provided his own blood for a transfusion; as they already shared the same blood type and DNA, his gamma-irradiated blood, combined with her anger, transformed Jennifer into the green-skinned She-Hulk when the mobsters tried to finish her off at the hospital. She then used her new powers to take down Trask, who was killed when the earth-boring device he rode malfunctioned, taking him to the center of the Earth.