One Piece Episode 339 -

Nami, Usopp, and Chopper head to the island first using the Mini Merry II. They find themselves trapped in a moat filled with skeletons.

After escaping the Cerberus, the landing party meets a vampire-like creature named Hildon. He offers them a carriage ride to the mansion of the famous surgeon, Dr. Hogback, a name that shocks Chopper. One Piece Episode 339

The trio is chased by a massive three-headed beast, which Chopper humorously notices has one head that is actually a fox rather than a dog. Nami, Usopp, and Chopper head to the island