Metal Cooler is the enhanced, mechanical version of Cooler, Frieza's brother, appearing in the Dragon Ball Z movie 'The Return of Cooler.' After his defeat on Namek, Cooler is revived and rebuilt by the Big Gete Star, becoming Metal Cooler. He serves as the main antagonist of the film, leading an army of robotic duplicates in an attempt to conquer the universe. Metal Cooler is significantly stronger, equipped with advanced regeneration and weaponry, posing a formidable threat to Goku and Vegeta.