The Gillman's Boss resemble a blue version of the Metarex Gillman.
The Gillman's Boss served as the superior of the Metarex Gillmans during the Metarex occupation of a desert world turned ocean planet by their possession of the Planet Egg. The Boss briefly had Sonic the Hedgehog held captive, and was going to feed him to his pet shark. However, Amy Rose intervened to save Sonic, and Gillman's Boss and his underlings were subsequently destroyed.
Powers and abilities
The Gillman's Boss was armed with a trident and torpedoes.