Prior to its mutation, the shark was a gray-colored hammerhead shark. After its mutation, the Mutant Shark's dorsal fins were transformed into a row of sharp back spines running from the top of its back to the beginning of its tail fin, which became much longer. Its pectoral and pelvic fins were transformed into forelimbs and hind limbs ending in clawed and webbed fingers, and it gained an additional pair of eyes.
The Mutant Shark was created by Valtor to keep the Winx occupied while Obscurum and the Staryummies attacked the core of Gorgol. It then ambushed the Winx and engaged in a lengthy battle against them. After realizing that their Sirenix magic cannot cause direct damage to the monster, Aisha suggests that the Winx would have to destroy Valtor's dark magic to make the Shark normal again. As for now, the Winx contained the Mutant Shark inside a cave.