The angrier he gets, the stronger he gets—and Bruce Banner's gamma-irradiated alter ego has gotten angry enough to crack continents and punch through dimensions. The Hulk's strength has literally no known upper limit, he regenerates from virtually any wound, and his thunderclap can level city blocks. The only thing scarier than fighting the Hulk is the realization that he hasn't even started trying yet.

Born James Howlett but known to the world as Logan, Wolverine is the Canadian mutant who simply refuses to stay dead. His adamantium-laced skeleton is virtually indestructible, his healing factor can regenerate from a single cell, and his razor-sharp claws slice through anything short of Captain America's shield. Three centuries of combat experience make him the best there is at what he does—and what he does isn't very nice.