She-Hulk (Jennifer Walters) is a Marvel Comics superheroine. Created by writer Stan Lee and artist John Buscema, she first appeared in Savage She-Hulk #1 (February 1980). She-Hulk has been a member of the Avengers, the Fantastic Four, Heroes for Hire, the Defenders, Fantastic Force, and S.H.I.E.L.D. A highly skilled lawyer, she has served as legal counsel to various superheroes on numerous occasions. She is the cousin of Bruce Banner, better known as the Incredible Hulk.
Jennifer Walters, the cousin of Bruce Banner (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 seventeen). Operatives of Nicholas Trask, a crime boss who had crossed paths with her father, shot and seriously wounded her on a day that Bruce Banner happened to be in town for a visit. 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 radioactive blood, combined with her anger transformed Jennifer into the green-skinned She-Hulk when the mobsters tried to finish her off at the hospital.
Source: Wikipedia, "She-Hulk", available under the CC-BY-SA License.