As with other members of Davy 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. Maccus was one of the four most trusted mates aboard the Flying Dutchman, along with Ratlin, Penrod, and Angler. He seemed to share Davy Jones' penchant for causing pain and destruction. When Jones ordered his crew to summon the Kraken to destroy the Black Pearl, Maccus gave the command with an evil, leering smile. He was also an expert swordsman, as evidenced during the fight for the Dead Man's Chest on Isla Cruces. Here, Maccus battled the trio of Elizabeth Swann, Pintel, and Ragetti, fighting them into a corner before they were rescued by Will Turner and Admiral Norrington. His main weapon of choice was a single-handed boarding axe. He lead the other crew mates to Isla Cruces because Davy Jones cannot go to land. Maccus continued to serve on the Flying Dutchman during the reign of Lord Cutler Beckett. During the battle between the Black Pearl and the Flying Dutchman in the maelstrom, Maccus attempted to kill Will Turner, but was in turn attacked by Jack the Monkey. Like most of the crew, he reverted to his human form.