Zummi Gummi is the oldest of the Gummi Glen Gummis. He is the keeper of Gummi wisdom, and later, the holder of the Gummi Medalion, who Cavin left for them, to open the Great Book of Gummi which he uses to cast spells and becomes the group's wizard.
He is forgetful and clumsy, often mis-speaking words with spoonerisms, and his spells tend to backfire. He also had acrophobia (fear of heights) later on. He was voiced by Paul Winchell (up until his death), and later by Jim Cummings.