Brad Carbunckle's little brother from blood, Tucker Cornelius Carbunkle (voiced by Audrey Wasilewski), is usually tagging along with his brother and Jenny, though his aptitude for adventure is significantly less than Brad's. This can be chalked up to his many childish fears, among them the dark and giant wheels. In spite of all his fears, after adventures or life threatening experiences, he will often shout "That was awesome!" and talk about what happened. Despite initial fears of Jenny, Tuck has since warmed up to her as a friend.
Tuck has proven to be more clever than he looks on several occasions, often sweet-talking Jenny and others into doing favors.