Serpentus

Serpentius is the guardian of the Ultragem in Castle Grimm on the Planet Gremlyn. He’s one of many obstacles people hoping to steal the Ultragem must face, and when Xenor Krell stumbled across it Serpentius nearly ate him alive, however luckily for Xenor Krell Amy Rose and Tekno arrived via the Eternity Ring at the precise moment. Although Serpentius’ thick hide protected it from Amy’s crossbow it fled from them. Serpentius returned but to late, Amy Rose had already given the Ultragem to Xenor who used it to transform the Ultragem into mist… It appeared in Sonic the Hedgehog comic #152 and 153.