Maccus served as First Mate aboard the Flying Dutchman under Captain Davy Jones. As with other members of Jones' crew, over time Maccus took on characteristics of the sea flora and fauna they resided amongst; most notably, his scarred head had the appearance of that of a hammerhead shark, and had sharp, fang-like teeth much like those of a shark. During his painful mutation, his left eye migrated from its socket over to the left side of his extended hammerhead. Maccus' body was covered in coral, barnacles and starfish, and his left forearm and hand was encased in a lobster-shell gauntlet. Several pairs of lobster legs grew out of his back.