The Hulk is, of course, the alter-ego of Bruce Banner. Having been exposed to Gamma radiation in a laboratory accident, he gained the ability (or curse, depending on which way you want to look at it) to transform into a huge green brute - initially whenever he was angry, but now voluntarily. In the Hulk form, Banner gains insane levels of super-strength and durability, enabling him to go toe-to-toe with the Abomination, whom he eventually overcame after a long fight. Prior to that bout in Harlem, the Hulks durability had enabled him to survive a fall from a helicopter. He was then an extremely important factor in the victory against the Chitauri and Loki in New York, alongside the rest of the Avengers. He smashed the Chitauri like bugs and took down a gigantic Leviathan-like space whale with a single punch. He had previously duked it out with Thor, indeed seeming to best him in basic physical combat, after having taken a powerful strike from Mjolnir square in the face. Wait for Age Of Ultron to see how he does against Iron Man.
