Dexter's Laboratory (1996)

S1E7 Dexter's Rival

Mandark Astronomanov, a new arrival at Dexter's school, appears to outshine Dexter in every academic aspect. Determined to assert his dominance, Mandark pressures Dexter into closing his lab to boost his own lab's capabilities. Yet, with Dee Dee's unexpected assistance, Dexter succeeds in bringing down Mandark's lab, turning the tables on his rival.