The Knautilus is Baron K. Roolenstein's secret submarine docked inside the secret world Krematoa in Donkey Kong Country 3: Dixie Kong's Double Trouble!. It is a fish-shaped submarine where Baron hides after his defeat in KAOS Kore. The sub is accessed by beating all Krematoa levels and giving all the cogs to Boomer. With all the Cogs, Boomer will use them to activate the machine, which causes Krematoa to return to volcanic activity and reveal the submarine.