Underdog(1964)

Underdog is an American animated series that aired Saturday mornings from 1964 to 1967, first on NBC then CBS. The show follows Shoeshine Boy, who transforms into the heroic Underdog whenever his love interest Sweet Polly Purebred faces danger from villains like Simon Bar Sinister and Riff Raff. Known for its distinctive style, Underdog speaks almost entirely in rhyming couplets, delivering his famous catchphrase: "There's no need to fear, Underdog is here!" The series ran 62 episodes during its original broadcast and remained in syndication through 1973, establishing itself as one of early television's most memorable Saturday morning cartoons.