Incidental 27 (named JimmyGus) is a background character who makes many cameo appearances throughout the series, starting in the episode "Ripped Pants."
He is olive green and so are his fins and lips but his fins and lips are slightly brighter. Jimmy has a golden-yellow dorsal fin and wears a light purple shirt and blue shorts. His eyes were yellow in earlier seasons, but in later seasons, his eyes are white.
Sometimes, Jimmy wears a black top hat with a magenta-red strip. He usually appears without his top hat.