Paper Mario: The Thousand-Year Door Tips

On that pirate island (forgot what its called get off the boat, go to the cave where bobbery blow a hole in but dont go in it, go left from it then stay still for a few seconds and a whack-a-mole show up, he only talks about the weather, hit him with a hammer and he will drop a roll called a "Wacka-Bump", hit him too many times and he will hide away