Ankoro

Ankoro is a gigantic angler fish under the command of captain Vander Decken IX, residing in the Underworld of the Sea, 7000 meters underneath the ocean surface. It tried to eat the Straw Hat Pirates and their ship, the Thousand Sunny, but was stopped by Wadatsumi. Wadatsumi seems to regard Ankoro as a pet, apparently Ankoro has needed to be told to "not eat ships" before.