The Klabautermann

The Klabautermann is a Fae, Kobold, Ancestral Spirit, God or Goblin depending on who you ask that resides upon ships in German folklore. In many traditions he is the soul of the ship itself or the tree that was used to make the ship. In some rare instances he is even said to the be the soul of a child who was buried under the tree that was used to make the ship, among other potential origins.
The Klabautermann is often depicted with a beard, pipe, woolen hat, raincoat and a hammer that he uses to fix up the ship he is a part of. Sailors keep an idol of their Klabautermann tied to one of the masts thanking him for his hard work. If his hard work was ignored he would play pranks on the crew.
As the soul of the ship, if the ship was well cared for the Klabautermann would bring good luck to the crew even helping keep the ship afloat or speaking to the sea on their behalf.
If a Klabautermann left the ship it would lose all its luck and sink.

They typically hang out near the Prow of the Ship and are unseen most of the time, some say they are only able to be seen when a ship is near its doom.