The planet is in the grip of Fuz-Z mania when a cute little creature becomes one of the most popular pets in Acmetropolis thanks to Professor Zane, who says that he found them shortly after the meteor strike. The pets become so popular that even Lexi gets one for herself. But when an attack occurs involving a mysterious creature, the team suddenly learns the truth that the Fuz-Zs are the attackers and are spurred on by eating chocolate, causing them to grow and attack. The Loonatics enact a two-step plan to get the creatures out of Acmetropolis while stopping Professor Zane.