The Hulk
Child prodigy Bruce Banner became a weapons researcher for the US Army, where he was inadvertently exposed to the radiation of a prototype Gamma Bomb. This granted him the power to transform into the nearly invulnerable Hulk -- but at the cost of suffering the consequences of the Hulk's unthinking rages.
Current Version:
The Hulk (Savage)
Alternate Versions:
The Hulk (World War Hulk)
The Hulk (Avengers)
The Hulk (Grey Hulk)
The Hulk (Avengers: Age of Ultron)