"Dexter's Laboratory" 1996

Dexter, a boy-genius with a secret laboratory, constantly battles his sister Dee Dee, who always gains access despite his best efforts to keep her out, as well as his arch-rival and neighbor, Mandark.

Cast:

Candi Milo
Dexter (voice) 

Kat Cressida
Dee Dee (voice) 

Jeff Bennett
Dad (voice) 

Kath Soucie
Mom (voice) 

Eddie Deezen
Mandark (voice)