A Royal Marine who asked to be made stronger, got what he asked for twice over, and spent fifteen years learning to live with it.
Emil Blonsky is a soldier who could not accept being outmatched. He takes an unfinished version of the serum to keep up with the Hulk, it works, he asks for more, and the second dose plus gamma radiation makes him something that cannot be undone.
What makes him worth an entry is the third act, fifteen years later. She-Hulk picks him up in prison, has him apply for parole, and treats his rehabilitation as genuine rather than as a joke about a monster doing yoga. It is one of the few times this catalogue lets a villain simply grow up.