Brook

Klabautermann

クラバウターマン
A Klabautermann is said to be a water spirit (or fairy) that dwells on ships that are well cared for and is basically an incarnation of the ship. It is a merry and diligent creature that is said to warn sailors when a ship's in danger and help in bigger ways sometimes. They are normally considered to be only a legend among seafarers. (Source: One Piece Wikia)