Snakehead!."Mother Duck" and her ducklings discover a monstrous snakehead fish living in their pond. They ask for the penguins' help getting rid of the deadly fish, which the penguins try to accomplish by building a submarine. Everyone except Skipper is afraid of the fish, so when the submarine gets stuck in an old tire, Skipper goes outside to untangle it and is swallowed by the giant fish in the process. The remaining penguins, under Kowalski's leadership, forge ahead to avenge Skipper. At the end, the others see that Skipper is alive in the mouth of the fish and toss him a bottle of soda that had been shaken up earlier when Julien tried christening the submarine. It causes the fish to blow up, and it is soon served as sushi by the penguins.