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

The U.S. army invades Dexter’s lab under the mistaken impression that aliens are using it as a base of operations on Earth, and Dexter must convince them that this is actually his lab, and also has to keep this a secret from Dee Dee.

Dexter’s father sleepwalks into Dexter’s lab. Dexter discovers this, and now has to escort him out of the lab without waking him up, which proves more difficult than thought.

When Dexter’s father tries to teach his son sports, he realizes that Dexter is not athletic.

During a trip to his grandfather’s house, Dexter learns that the outwardly boring old man has a lab just like his own.

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.

With only one television in their apartment, Major Glory, Krunk, and Valhallen disagree on what to watch: Major Glory’s televised capture of the Disgruntled Postman, TV Puppet Pals, or the monster truck pull.

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.

Dexter creates a device that turns people into hideous blobs. His parents then sell the device in a garage sale, where it ends up in Mandark’s hands.

When Dexter uses anti-matter on the family car to shorten road trips, he accidentally fuses Dee Dee with the car.

After watching a horror film, Dexter and his father become easily frightened.

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.

When his television show is interrupted by the Emergency Broadcast System, Dexter sets about fixing any emergencies in the neighborhood to make the signal go away.

Dexter and Dee Dee protect their mother’s muffins from their muffin-loving father while she is out shopping.

Dexter and Dee Dee refuse to flush their dead goldfish into the toilet and are later haunted by its spirit.

Following the destruction of his lab by Dexter and Dee Dee (in the episode Dexter’s Rival), Mandark turns to magic to beat Dexter at the science fair.

In need of an assistant to operate his latest invention, Dexter performs a brain transplant on Dee Dee to make her smart enough to fulfill the role. With her new brain, Dee Dee proves to be more intelligent than Dexter.

After Dee Dee steals his critical invention, Dexter ventures into her room to find it.

Major Glory, Krunk, and Valhallen try to rid their apartment of a bee.

Dexter tries to move the Moon, which is blocking Saturn and its “science waves” (which is what makes it a “good day for science”).

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

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 makes his own Major Glory action figures so that he can join the neighborhood’s Major Glory gang, but gets into serious trouble when the rest of the gang finds out that none of his action figures are original.

When Dee Dee eats a contaminated apple, she turns into a monster every time when she tells Dexter what to do.