When their father makes Dexter and Dee Dee switch rooms, Dexter believes that Dee Dee is destroying his lab and destroys her room in retaliation.

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.

Following a mishap in his lab, Dexter ends up in the old, long-abandoned part of the lab, and discovers his early, neglected inventions.

While fighting Comrade Red and his gang, Krunk falls in love with his equivalent in their gang, She-Thing (Kath Soucie).

Dee Dee befriends a sasquatch during a camping trip, but Dexter is determined to capture the sasquatch.

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

When Dee Dee befriends a turtle that gets severely injured, Dexter not only heals it, but gives it superpowers.

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 and his father enter a golf tournament, but Dexter’s father proves inept at the sport.

Dee Dee builds a tree house and allows everyone inside except Dexter, in revenge for the times he kicked her out of his lab.

When Dexter is tired of Dee Dee’s bad singing, he tries to transform her voice, but he ends up giving her a baritone voice (Kevin Michael Richardson).

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’s father plays golf with his kids.

Dexter and Koos must save Peepers to keep the land of Kooz from disappearing. However, they must contend with a villain who is determined to make the land of Kooz disappear forever.

To clone a dinosaur with an incomplete DNA sequence, Dexter uses his dog’s genetic code to fill in the gaps.

Dexter’s mother asks him to read a story to a sick Dee Dee. Dee Dee becomes bored of Dexter’s story and creates one of her own.

After fellow Justice Friend White Tiger helps Valhallen stop a super-villain, the latter invites him to spend the night in his apartment, forgetting that Major Glory is allergic to cats.

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).

Dexter accidentally gives himself telepathy that he cannot shut off when trying to overhear his father’s thoughts to figure out what he got for his birthday, causing everyone to accidentally read his own mind.

Dexter’s newest invention looks like a hat, so Dee Dee takes it and wears it around town.

When his family is suffering from the flu, Dexter tries his best to not acquire the illness, but his efforts are thwarted by a sick Dee Dee’s presence in his lab.

Dexter brings the cavemen who first discovered fire back from the past, who acts like Dee Dee and starts smashing the lab.

Dexter tries to avoid being pushed into the family’s new swimming pool by his father, since he cannot swim and is afraid of water.

Mandark’s birth and origins as the child of hippies are revealed, as is the beginning of his rivalry with Dexter and the cause of his villainy.