Bio Lizard

Bio Lizard is the prototype to the ultimate life form. He was created by Gerald Robotnik to be an immortal creature but instead Bio Lizard was locked away by G.U.N. He eventually was released and it was revealed that Gerald had used him in a plan to destroy Earth. Sonic the Hedgehog and Shadow the Hedgehog eventually stopped Bio Lizard using the power of the Chaos Emeralds.