Dr. Baxter Stockman is a knowledgeable but sociopathic scientist off, who used his talents to achieve his own selfish goals rather than helping mankind. His latest invention, the Mousers, were small robots designed allegedly to find and exterminate rats in New York City, thus solving the city's rat problem. He developed the Mousers with the help of his software engineer, April O'Neil. Around the time when Baxter completed his invention, mysterious bank robberies were being committed, with small tunnels leading into the vaults. the Rat King happens upon the Teenage Mutant Ninja Turtles and their friend Casey Jones, who had come to the industrial park to train. Believing the Turtles and Casey to be other "monsters" who wish to take his territory, the Rat King proceeds to stalk them throughout the park, even capturing Michelangelo and leaving him to be devoured by the rats (Michelangelo later escapes). The Rat King is eventually defeated by Leonardo who, in a duel with the Rat King, flings several shuriken at him, which impale the Rat King and knock him off balance, sending him plummeting into the bowels of a silo.
