One Piece: Umi no Heso no Daibouken-hen  

One Piece Special: Adventure in the Oceans Navel, ワンピース ルフィ落下!秘境・海のヘソの大冒険, One Piece: Adventure in the Ocean's Navel, ONE PIECE TV Special: Umi no Heso no Daibouken-hen, One Piece: Avventura nell'ombelico dell'oceano, One Piece Special: Adventure in the Ocean's Navel, วันพีซ ภาคพิเศษ 1 การผจญภัยใต้มหาสมุทร

In the middle of a whirlpool known as the Oceans Navel, the Straw Hats come across a city that's being destroyed by enormous monsters. These creatures are said to safeguard a treasure with the power to make wishes, but in their efforts to vanquish these guardians, they unleash another malevolent force. This event occurred after Episode 53 of the series.