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"The Big Sister"
"Old Man Dexter" Rightarrow
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"The Big Sister"
"Old Man Dexter" Rightarrow
The Big Sister
Season 1, Episode 002 / 6c
The Big Sister
Air date March 10, 1996 (first airing)
June 1, 1996 (TNT; sneak preview; second airing)
June 2, 1996 (TBS and Cartoon Network; third airing)
Production number 002 (Pilot)
104c (Series)
Written by Genndy Tartakovsky
Storyboard by Mike Moon (Background Design)
Directed by Genndy Tartakovsky
Craig McCracken (Art Director)
Paul Rudish (Art Director)

The Big Sister is the second pilot of Dexter's Laboratory, which aired on March 10, 1996. It re-aired on June 2, 1996 as the third part of episode 6 in season one. In this episode, Dexter makes cookies for his rats to test. When Dee Dee eats one, she grows into a giant and wreaks havoc on the city. Dexter must use his Robo-Dexo 2000 to bring her down.


After Dexter completes his latest invention, the Chemical X29, he decides to test on some rats and prepares them into cookies. Dee Dee quickly becomes aware of the delicious confections and makes her way to Dexter's room to eat them, but is quickly stopped, with Dexter warning her of their purpose. Dee Dee then dons on a rat costume and is able to trick Dexter into feeding her a cookie. She then grows extremely tall and goes on a "rampage" throughout the city with many believing her to be a "giant monster" due to her treating the city like her own doll collection. Dexter at first does not care, seeing this as an opportunity to spend some alone time, but as he watches the news report on the mass hysteria over the giant Dee Dee which even features a fearful plea for help from the President, Dexter begins to see himself as a world hero being thanked by world leaders, the science community, heavenly representatives and the very buxom Ms. Physics. This is enough to make him go out on the field and stop the "giant monster" with his Robo-Dexo 2000.

Upon confronting Dee Dee in the city, she quickly proves to be more than capable of outwitting Dexter, despite seeing his attempts to destroy her as a playful game. Dee Dee eventually damages the Robo-Dexo enough to force Dexter to eject himself from the cockpit, at which point Dee Dee is able to catch her tiny little brother and treat him like a dress-up doll, much to his mortification. Lucky for Dexter, he had invented an antidote cookie and was easily able to convince Dee Dee to eat it, turning her back to her normal size. But just as things seem to be going well for the two siblings, a real and hideous giant monster appears in the city who is none other than their Mom who had also managed to eat the X29 cookies Dexter had left out in the open. She then tells her two children to clean up their "mess" (the destroyed city), however Dexter is unable to cope with the situation and so passes out instantly while Dee Dee continues to savor the antidote cookie.


Voice Cast


  • The title of this episode is a pun on how Dee Dee is Dexter's older sister A.K.A. his big sister, hence the title of this episode.
  • This episode marks the debut of the Robo-Dexo 2000.

Cultural References

  • The way Dee Dee grows really huge and destroys the city is similar to the way Godzilla did in the Godzilla movies.
  • When Mom enters Dexter's bedroom and is met by Dexter's robot duplicate, a Power Rangers-like poster can be seen on Dexter's bedroom wall.
  • Dexter imagines himself getting a phone call from God, congratulating him on saving the world.
    • This is one of the few times there has been a religious reference in Dexter's Laboratory.
  • In a part of the episode, there was an interview with the President of the USA. He was not seen and was only heard. It is most likely that this was Bill Clinton, because he was president when this episode was made and his voice is clearly a parody of Bill Clinton's.
    • This would be the first and one of three times the President of the USA is mentioned in the show. The second time being in "Critical Gas" (where he was actually seen rather than heard or mentioned and he was clearly shown to be Bill Clinton) and the third time being in "Let's Save the World You Jerk!".
    • When Dexter's mom enters his room, there is a reference to the five original rangers (red, yellow, pink, blue and black) of the 90's show Mighty Morphin Power Rangers. The Power Rangers franchise has grown a following since its debut and has produced collectible merchandise.

Production Notes

  • This is the second pilot of Dexter's Lab, and it aired during the What A Cartoon! Show.
  • This episode can be seen as an extra on a Scooby Doo video.
  • This episode aired twice in the series, once as a pilot and again as the final segment after "Dee Dee's Room" and "Dial M for Monkey: Huntor".
  • The episode is also shown as a bonus cartoon at the end of the Cats Don't Dance video tape after a Cartoon Network preview, which is shown after the movie.
  • This pilot is produced in 1995 according to the credits.


  • At the beginning of the episode, the plate of cookies was seen inside of Dexter's Laboratory, but later in the episode, it was seen in his bedroom.
  • At the end of the episode, Mom had turned into a giant mutant because she ate the cookies and she saw what happened. This means that she had figured out about Dexter's Laboratory and its secrets. However, she seems to have still remained oblivious to it in the later episodes.