It is revealed in episode "The Lesson" that he and the Turtles had met when they were kids, although neither the Turtles nor Casey are aware of the truth. During a trip to the surface, the young Turtles witness bullies picking on young "Arnie". Disguising themselves as a human child, they attempt to teach him self-defense. However, their unique perspectives and attitudes resulted in more trouble than help. In the end, however, young Casey angrily jumps to the defense of a friend against the bullies, proclaiming they were no match for "Arnold Casey Jones!" In a bit of foreshadowing, he uses a bully's hockey stick against them.