A modified version of the 1958 soul song Yakety Yak by The Coasters is used as the series' theme song.
Characters
Yakkity Yak : A yak student in Onion Falls Junior High School and the school's mascot who wishes to be a comedian. Yakkity works as the school mascot since his grandfather also served as mascot when the football team won the state championship in 1925. The football team, instead of the mascot, got all the glory, much to Yakkity's distaste. Yakkity now lives with his Granny and her boarder Professor Crazyhair. He wears a coat over his bare body. His closest friends are Keo and Lemony. Over the course of the series, his parents have never been seen or mentioned.
Keo : An anthropomorphic pineapple who is actually a human with a pineapple for a head. He is very intelligent but is camera shy and has stage fright. He has rivalries with his father who is only a pineapple, but deep down, he loves him.
Granny Yak : Yak's grandmother. While she is a good sounding board in a parental way, she also has some of Yakkity's impulsive genes.
Lemony : A blond-haired human girl who has a vivid imagination.
Reginald Highpants : The town's leading vendor of candy and all things with sugar. He also runs many small businesses.
Trilo : Yakkity's trilobite agent and former circus performer who owns his own Entertainment Agency, does children's parties for the characters, and is always looking for money. His clients are Yakkity, Fairy Wanda and Chuck Damage, who he uses for parties.
Professor Crazyhair : A scientist and teacher at Onion Falls High whose hair changes colour like a mood ring, hence his name. He lives in Yakkity's basement, where he built a laboratory.
Penelope : A robot who is Lemony's best friend and works as Professor Crazyhair's assistant but lacks any social skills or confidence. Whenever she's embarrassed, her face turns red and she squirts out fire fighting foams from her arms transforming into fire hoses, squirting everything around her.
Rondo : Lemony's football playing brother who is a senior in high school. He is one of Yakkity's main antagonists often competing for the spotlight.
Keo's Dad : A pineapple who can be bossy and rude at many times, and Keo's father. The identity of his wife is unknown and never explored; it can be assumed that she either died or got divorced before the events of Yakkity Yak.
Wanda Harper : a fairy who works as Onion Falls High's librarian.
Jackie Pachyderm: An elephant comedian and successful movie star who is Yakkity's idol.
