The Hulk's primary physical adversary is the Abomination, a "massive, green-skinned monster" that can hold its breath for abnormally long periods of time. This, of course, is a perfect description of our reptilian rivals to the south, the Florida Gators.
a.k.a. The Florida Gators
Like the Hulk, the Abomination "belongs to a small minority born with a genetic factor that cause[s] them to mutate . . . ." Exhibit A:
Genetic abnormalities? You be the judge.
The Abomination is twice as powerful as a calm Hulk, and two defeats in a row [and now 7 of 8 -- ed.] at the hands of the Hulk have driven the Abomination insane with hatred toward Banner and his boys. So is it a lost cause? No, because the Abomination's powers and abilities, while awe-inspiring, do not increase or decrease based on its emotional state. The Hulk's, on the other hand, do. Remember that "the madder Hulk gets, the stronger Hulk gets," and an enraged Hulk can and will overcome the Abomination. You know, like [2005-06] during the regular season.