Fuz-Z's are lifeforms that were created and released to the surface after the 2772 meteor.
Originally introduced to Acmetropolis as biopets, the Fuz-Z became immensely popular in the city. Everyone bought one, including Lexi and Duck (Although Duck’s never arrived). Small and cute at first but after the Fuz-Z’s consume chocolate they become mutants that attack everything in sight.The amount of time the transformation last depends on the amount of chocolate they eat.
Further investigation revealed that the biopets were life forms released by the 2772 meteor. Professor Zane found the biopets and conducted experiments on them. When his plan was discovered he attempted to use the Fuz-Z’s to attack the Loonatics but they stopped him before he could feed all the Fuz-Z’s chocolate. After Professor Zane was captured, the Loonatics transported the Fuz-Z’s underground where they can live peacefully without chocolate.
- In The Family Business, a monster that looks a lot like a Fuz-Z's mutant form makes a minor appearance.
- The Fuz-Z's are similar to gremlins from the 1984 film Gremlins in that that requre something in order to change.