Marvel Legends Hulk
While working at a nuclear research facility, scientist Bruce Banner was accidentally caught in a gamma bomb explosion. The blast transformed him into the monstrous, rampaging Hulk, a creature with childlike intelligence and superhuman strength, which he often directs against those who would threaten him or other innocent human beings. Ever since, when enraged, Banner turns into the Hulk and stays that way until the raging giant calms down and reverts to his normal human form.