Gaster is the main antagonist of the series. He appears to be a lilac-colored rabbit with dark green hair. Along with his assistant Gruber, he often causes trouble for Parappa and his friends. The law-breaking endeavors usually occur due to Gaster's dream to become rich. <br /> He often says his own name as an exclamation, which is used both positively and negatively during the series.<br /><br />