Dexter's Laboratory - Season 1 - Eps 25: Dollhouse Drama
Suspicious that Dee Dee has not entered his lab even once on a particular day, Dexter shrinks himself and enters her room to spy on her. He soon becomes an unwilling character in Dee Dee's doll story, but he believes the story to be real.
About Dexter's Laboratory

Title: Dexter's Laboratory
First Air Date: 1996-04-28
Last Air Date: 2003-11-20
Status: Ended
Rating: 7.7/10 (from 813 votes)
Language: EN
Seasons: 5
Total Episodes: 220
Network: Cartoon Network
Genres: Animation, Comedy, Sci-Fi & Fantasy
Production Companies: Hanna-Barbera Productions, Cartoon Network Studios
Synopsis
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)