Klabauterman

Klabautermen, also known as Klabautermanns, Klabotermen or Sea Kobolds, are a type of kobold originating in German sea-faring folklore.

Description
Klabautermen are kobolds who inhabit a ship. Like the household variety of kobold, klabautermen are extremely helpful; thus, they perform various repairs to their chosen vessel, steer it out of danger, and may even pull fallen sailors back aboard. They have an irrepressible affinity for music and usually make themselves down by their singing. Klabautermen are otherwise usually invisible, and only appear to sailors in times of utmost danger, making the sight of a klabauterman a very bad omen.

Inspired

 * Klabautermanns (One Piece)