O'Chunks is a large, bearded, and not too bright enemy from Super Paper Mario. He has a sort of Scottish, or Irish, accent. He is a boss in the game and is encountered numerous times. He is a minion of Count Bleck, along with Mimi and Dimentio. O'Chunks is battled multiple times, but fails miserably each time.
In each battle against O'Chunks the strategy is about the same. You use Thoreau to grab O'Chunks and throw him, then while he is injured by that jump on him. Then repeat that until he is defeated.