Metal Sonic is a major antagonist in the Sonic the Hedgehog series. Created by Dr. Eggman, Metal Sonic is a robotic doppelgänger of Sonic, designed to match and surpass the original hedgehog's speed and abilities. As one of Sonic's most persistent rivals, Metal Sonic is highly intelligent, fiercely competitive, and relentless in pursuit of his creator's goals. Throughout the series, he often challenges Sonic in high-speed battles, serving as a symbol of Eggman's technological prowess and determination to defeat Sonic.