Ribbit is an aqua-blue frog who looks very similar to Darwin, despite being a frog. He wears purple shorts and is barefoot. He has two toes on each foot and two fingers on each hand.
Akin to the relationship between Gumball and Chi Chi, Ribbit emulates everything that Darwin says and does. As shown in "The Copycats," the two share the same characterization as well, as when he is fighting against Darwin, they both flinch, then apologize upon hitting one another.
- "The Copycats": His debut and first major role. He and his family copy everything their Watterson equivalents do.
- Ribbit's design is heavily based on that of Quack/Gua-Gua's from Miracle Star, a Chinese knockoff of The Amazing World of Gumball, made to promote milk. In early TV guide summaries of the episode, the name "Quack" is used to refer to him.
- Ribbit's name is based on the sound that a real frog makes.