Nickodemus is a mule with a strong personality and a knack for adventure.
He is generally a tame creature and a children's pet: he lives with Fluff and Bud and Aunt Rivette, and gives the boy rides on his back. Yet he has a powerful kick and does not hesitate to employ it against suitable targets.
Once Bud becomes king of Noland, Nickodemus wanders off on his own; he is captured by bandits, but escapes. In the forests of Noland he encounters other animals. His habit of scratching and rubbing his hindquarters, on trees and other bodies, leads him into difficulties with the Zoop, and he also confronts a local "lazy lion." He is clever enough the let the Zoop and lion fight each other while he slips away.
A compassionate fellow, Nickodemus takes a liking to Mary, a young girl kidnapped by the bandits. He organizes a gang of animals, including the formerly hostile Zoop and lion, to attack the bandits and rescue Mary. Nickodemus returns Mary to her parents, and wins their gratitutde. Nickodemus also leads the animals in an attack on the Roly-Rogues after they invade the city of Nole.
Nickodemus is a character that L. Frank Baum added to the story of Queen Zixi of Ix when he wrote the script for the 1914 film adaptation The Magic Cloak of Oz. The mule was played by Fred Woodward, the actor who played Hank the mule and other animals in Baum's stage and screen works.
Woodward played mules in a costume that had him on all fours, hands and feet: the front legs of the costume had extensions that made his forelegs (that is, his arms) as long as his hind legs. He was strong enough to give rides to both the Bud and Mary characters (the children sat on his hips rather than his back).