CaptainAmericaRockz's Movies-Spoof of 'Underdog' Cast * Captain America (The Avengers: Earth's Mightiest Heroes) as Underdog * Starfire (Teen Titans) as Sweet Polly Purebred * Aku (Samurai Jack) as Thomas "Jack" Unger * Wolverine (X-Men Evolution) as Dr. Simon Bar Sinister * Gumball (The Amazing World of Gumball) as Tennessee Tuxedo