Dexter's Laboratory is an American animated television series created by Genndy Tartakovsky for Cartoon Network and the first original series for the channel under the Cartoon Cartoons moniker. The series follows Dexter, an enthusiastic boy-genius with a hidden science laboratory in his room, which he keeps secret from his unsuspecting parents. Dexter is at constant odds with his older and more extraverted sister Dee Dee, who regularly accesses the laboratory and inadvertently foils his experiments. Mandark, a nefarious boy-genius classmate who lives next-door to Dexter, attempts to undermine him at every opportunity. Prominently featured in the first and second seasons are other segments focusing on superhero-based characters Monkey, Dexter's pet lab-monkey with a superhero alter ego, and the Justice Friends, a trio of superheroes who share an apartment.