When Dee Dee tries to cut off a piece of her hair, she accidentally cuts off one of her pigtails. Dexter gives her a potion to make her missing hair grow back. However, Dee Dee squirts too much of it in her hair, and Dexter must return Dee Dee’s hair back to normal.

After Dexter orders and eats a giant burrito, he suffers severe stomach pains. Believing a test the computer gave him, he assumes that he has only 30 minutes to live.

Dexter’s family goes to the beach, where Dexter tries to communicate with whales. He must rescue Dee Dee (dressed as a mermaid), when she is captured by manic pirates.

When Dexter cannot get the ice cream truck to stop for him, he creates a series of obstacles to do so.

On his birthday, Dexter makes himself invisible so that he can find out whether his parents have bought him the Major Glory action figure he always wanted.

Rerun of “Dexter’s Laboratory”, the first What a Cartoon! pilot.

When Dexter learns that Dee Dee is trying to make a science project alone, he decides to help her, but she does not want his help.

Dexter and his friends are targeted by a bully at school for their multicultural accents.

Dexter travels to the moon and finds that aliens are planning an invasion on Earth, and he uses his Robo-Dexo 2000 to stop them. It turns out that they only were interested in purchasing sweaters for the winter.

To fix their apartment’s plumbing, Krunk and Valhallen go to the basement, where they meet Ratman (Maurice LaMarche), a diminutive vigilante raised by rats (a parody of Batman).

Due to overworking his brain, Dexter’s mind shuts down, making him act idiotic.

During a trip to Japan as part of a student exchange program, Dexter accidentally releases a giant monster with an axe-like head from a volcano, forcing him to enlist the aid of his family to defeat it.

Dee Dee enters the land of her imaginary friend Koosalagoopagoop.

Dee Dee teaches Dexter how to live life her way instead of being lonely and purely focused on science.

A nature documentary team observes “Blackfoot” (Dexter) and “Slim” (Dee Dee) in their “natural habitat”.

A little girl with big eyes falls in love with Dexter and follows him everywhere after he returns a toy she dropped earlier, much to his chagrin.

Quackor returns to battle Monkey in Dexter’s Lab until Quackor lays an egg; then the two fall in love.

Created and narrated by a six-and-a-half-year-old boy named Tyler Samuel Lee, who sent a tape containing the episode’s audio to Cartoon Network,[9] the story follows Dexter and Mandark’s robot “brother” Computress teaming up to make Mandark’s head shrink.

Dexter’s life story, from his birth to the creation of his secret laboratory, is retold as an opera.

A teleporter malfunction sends Dexter to an alien prison, prompting Dee Dee to go on a mission to save Dexter.

When Dexter is asked to bring his mother to school, he disguises Dee Dee as her so that she can take her place, but Dee Dee does not behave like their mother.

On Mother’s Day, Dexter’s mother has her gloves taken by the family so that she can relax and not do housework, but she is unable to adjust to a life where she cannot keep the house clean.

When Dexter discovers that Beau, Dee Dee’s new boyfriend, has similar interests as him, Dexter tries to steal Beau’s attention from Dee Dee.

It is Career Day, and because Dexter is ashamed of his father, he creates a better father for himself. However, he soon discovers that his real father is much cooler.