9. Ultimate Hulk
Over in Earth-1610, otherwise known as the Ultimate Universe, there exists a Hulk, and he's considerably more brutal than any other incarnation. This version of the Hulk is different from others in that he isn't a separate character from Banner. Instead, he's the manifestation of Banner's Id, making him a mirror of Bruce.
Ultimate Hulk is a being of pure rage, and he utilizes the base emotions that Benner tends to repress, but at degree, that is exponentially greater than anything even remotely controllable. In several stories, the Hulk had to be reigned in by the Ultimates because he doesn't stop when he should.
The Ultimate Hulk is otherwise similar to most versions of the Hulk in that he has an unlimited strength level, which is determined by his rage. He also possesses a great degree of invulnerability, has superhuman hearing, stamina, durability, speed, and healing.
While the Hulk has fought alongside the Ultimates, he's barely in control compared to the other heroes. He's hardly a hero when you get down to it, and is more of an unstoppable rage monster who enjoys picking people up and eating them. He's far less a hero and more of a villain due to his behavior.