Hulk

The Hulk is the alter-ego of Dr. David Bruce Banner, an American scientist who was experimenting with gamma radiation, trying to create a cure for diseases and access hidden genetic strengths, which instead unleashed a manifestation of his repressed anger in the form of a gigantic green monster

Whenever Banner is enraged or under extreme emotional stress, he transforms into the Hulk, a childlike beast which will destroy anything in his path to be left alone by tormentors. However, the Hulk is capable of good and is therefore a valuable asset to the superhero team the Avengers.

Biography
Bruce Banner was born as the son of Brian Banner, an alcoholic with verbal-abusive tendencies. Banner had a condition which prevented him from almost ever venting anger or frustration, bottling it up in his mind in an unhealthy fashion.

When working at Culver University, he became romantically involved with Betty Ross, an intelligent young woman who aided him in his gamma research. When facing a dilemma about tapping into hidden strengths to save lives, Banner worked on a device based on gamma research that would help him explore further. Betty's father, General Thaddeus Ross, funded his research in the hopes of perfecting a new super-soldier serum.

The experiment seemed to have no effect on Banner, until one night his car broke down in the rain on the way home from work, and he began to release decades of anger in his system. The gamma radiation manifested the anger into the incredible Hulk, a monster of pure adrenaline and rage. The creature has been falsely accused of actually killing Bruce Banner.

Banner now travels around the United States, searching for a cure. He assumes different identities to cover his tracks but is constantly hounded by Jack McGee, an investigative reporter. However, he is given the choice to use the Hulk for good when he is invited by the Avengers.

Powers
The Hulk's main superpower is his superhuman strength. Whenever he gets angrier, he gets stronger, making putting him down a tricky business. He is also able to leap at large distances and withstand bullets, fire and radiation. His healing factor takes care of any wounds.