Mertock is one of the supporting antagonists of Treasure Planet and one of the alien pirates in John Silver's crew. He seems to be a purple anthropomorphic manatee with clawed fingers, coiled tentacles that serve as his two legs, and a pudgy horn-like limb that sprouts from his head.
He is voiced by Dee Bradley Baker.
Trivia
- His voice actor, Dee Bradley Baker, also voiced Longbourne in the film.