He-Man and the Masters of the Universe

Merman attacks a seafaring hermit called Jacob with some mechanical sea monsters, but his attack fails and He-Man, Teela and the Widgets rescue Jacob. Merman thinks he could use the Widgets' Coridite to make his mechanical demons stronger, so he sets up a scheme to steal the Coridite. He-Man and his friends must stop Merman, with the help of Jacob.