The Incredible HULK
Played by: Mark Ruffalo (with the voice of Lou Ferrigno)
First appeared in comics: "The Incredible Hulk," May 1962
First appeared on TV: "The Marvel Super Heroes"; and, more memorably, in "The Incredible Hulk" live-action series (played by Bill Bixby and Ferrigno) from 1977 to 1982
First appeared in movies: Three made-for-TV movies starring Bixby and Ferrigno (1988, 1989, 1990); "Hulk" (played by Eric Bana), (2003); "The Incredible Hulk" (played by Edward Norton, with Ferrigno's voice) (2008)
Who and what: While attempting to weaponize gamma rays, Banner was dosed by radiation, causing a Jekyll-and-Hyde-like condition that transforms him, whenever his anger or sense of self-preservation rises, from a mild-mannered scientist into a super-powered, raging, incoherent green behemoth. The Hulk possesses none of Banner's intelligence or rationality and is a serious danger even to those friendly to him.
Dr. Bruce Banner is a mild-mannered scientist who was hired to replicate the Super Solider(that made Captain America decades before) for the US army. But, with a high exposure of gamma-radiation instead of vita rays, turns into an uncontrolled green-skinned rage monster known as the Hulk. Now, fearful of the damage that the Hulk could inflict, Dr. Banner chooses to live a discreet life in remote parts of the world, working to cure the sick and help the poor while trying to elude those who would take advantage of his ability to change into the enormous, green menace. Banner, driven to the brink once supposedly took out a gun and tried to shoot himself in the mouth. He transformed into the Hulk and spit out the bullet.