Dexter's Laboratory (1996)

Dexter, a brilliant young inventor, secretly operates a high-tech laboratory filled with amazing experiments. However, his plans are frequently thwarted by his mischievous sister, Dee Dee, who effortlessly infiltrates his domain despite his attempts to barricade her out. Complicating Dexter's life further is his cunning neighbor, Mandark, who poses as a formidable rival. The comedic clashes between Dexter's intellect and the chaos unleashed by Dee Dee and Mandark create a whirlwind of mischief and adventure in this animated classic.