Cujo is a little person, barely reaching Wheeler's waist, and is initially the main suspect behind the accidents the Planeteers deal with while they work undercover at the circus. It is soon revealed, however, that Cujo is kind and generous, feeding the animals behind Madame Mao's back.
Cujo has brown hair and wears a red shirt, a brown hat and blue coveralls. He can sometimes be seen carrying a brown sack, usually containing food for the various circus animals.
After Madame Mao's arrest, Cujo says that he will take over the circus, but leave the animal acts out and focus more on trapeze artists, clowns and acrobats in order to avoid animal cruelty.
Ma-Ti is petting the tamed lion.
Ma-Ti: Nice kitty!
Cujo: Looks like you made a friend!
Wheeler: Don't play innocent, Cujo, you lousy sneak! We caught you red-handed!
Cujo throws a steak in towards the lion.
Cujo: I guess you did. But I gotta sneak! Because if Madame Mao sees that I'm feeding the animals, she'll fire me!