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Barrel Ball is Donkey Kong's Star Pitch in Mario Super Sluggers. Donkey Kong will throw a barrel instead of a ball when the pitch is used. Hitting it will break the barrel and the ball will be hit. Like with any other possible captain, if Donkey Kong is the captain, it will use up one star on the star gauge. If Donkey Kong is not the captain, it will use up two stars on the star gauge.
If the batter doesn't hit the barrel hard enough, the baseball won't fly very far, which makes it easy for fielders to get the batter out. Therefore, the batter should charge up their swing before hitting this Star Pitch.