Turtles at the Earth's Core (S03E10)

After witnessing a living dinosaur wander in the city and disappear abruptly, the Turtles follow its tracks into a large hole, where they discover a shocking revelation: A land frozen in a stage where dinosaurs roam the land. Meanwhile, Shredder and his mutant goons, Bebop and Rocksteady, are also there, but to collect a crystal needed by Krang to recharge the power cells of the Technodrome. The Turtles discover that the crystal is the life force for the entire dinosaur population and must get it back before they are all destroyed. (iTunes)