Susan "Mandark" Astronomanov is the main antagonist in Dexter's Laboratory. He is Dexter's rival and later mortal nemesis who often seeks to destroy both Dexter and his lab to prove once and for all that he is the superior genius.
Vote which fictional character would naturally fit in-universe with a big-named franchise! No time-travel, no interdimensional crap, no "Pooh's Adventures", they would just exist in-universe.
