Maximillian Greco is a villain in Street Sharks.
During the course of his debut episode "Shark Father," Greco discovered Dr. Paradigm's secret as a fake savior of the city and blackmailed Dr. Paradigm into gene-slamming him with rhinoceros hair "collected" earlier by Killamari as well as the DNA of a desert tortoise. The gene-slam granted Maximillian Greco the strength of a rhinoceros and the longevity of a desert tortoise which de-aged Greco to half his age. He later had Dr. Paradigm further enhance him to take on the Street Sharks.
Maximillian Greco later returned in "Card Shark" where he was running a casino called the "Golden Greco." He ends up discovering the plot of Repteel and Shrimp Louie to rob his casino. Maximillian Grecko later used them and Killamari to rob his competitors. During the fight with the Street Sharks, Dr. Paradigm arrived and fought Maximillian until the casino collapsed on top of them.