Dexter and Mandark are both outperformed by a new girl at school, so they reluctantly team up to get rid of her.

Mandark Astronomanov, a new student at Dexter’s school, seems to be superior to Dexter academically. Mandark forces Dexter to shut down his lab so that Mandark’s lab can gain more power. However, with the help of Dee Dee, Dexter manages to destroy Mandark’s lab.

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.

Dexter and Mandark team up to fight asteroids that are heading towards the Earth.

Intergalactic wrestling champion Rasslor (“Macho Man” Randy Savage) challenges Earth’s superheroes, including Monkey, with the planet’s fate at stake.

When Dexter tries to inject himself into an ill Dee Dee to find a cure to the common cold, he accidentally ends up inside his dog, believing that Dee Dee is infected with a dog virus.

Dee Dee dares Dexter into building her a giant robot similar to his Robo-Dexo 2000. They then team up to try to save an island’s population from being destroyed by an erupting volcano using their giant robots.

Dexter’s mother attempts to support him during a chess tournament but does nothing but embarrass him.

Dexter’s Magic Uncle Fergel O’Reilly (Mark Hamill) pays a visit to the family.

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

Dee Dee enters the land of her imaginary friend Koosalagoopagoop.

Dexter falls in love with a new girl at his school, but he cannot win her heart until Dee Dee helps him with poetry

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.

Dexter tries to improve his eyesight by giving himself laser eye surgery, but goes too far in doing so.

Dee Dee learns a new game that can predict the future events.

To learn more about girls, Dexter camouflages himself and enters Dee Dee’s room, where she is having a sleepover with her friends Lee Lee and Mee Mee. He gets caught by the girls, who force him to take part in their activities.

Dexter “fires” Dee Dee, only to realize that the chaos she causes has been helping him concentrate.

Dexter’s father plays golf with his kids.

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

Dexter and Mandark drill underground to expand their labs, but end up running into each other’s work. So they agree to share the lab, inducing chaos.

Dexter catches the chicken pox, and Dee Dee tells him a ridiculous tale that if he keeps scratching them, he will turn into an evil chicken. Dexter completely restrains himself so that he will not have to scratch it; unfortunately, he is unable to resist and his nonstop scratching eventually does just that.

Dexter travels to Mars to find intelligent life, unaware that Dee Dee has stowed away in his space capsule. After Dee Dee gets covered in red dirt, Dexter thinks she is a real-life Martian.

Despite warnings from the computer, Dexter consumes too much power while performing numerous experiments, causing his lab to shut down.

Dexter pirates cable for his father.