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

When Krunk gets a tortilla chip stuck in his tooth, Major Glory decides to fix it by pulling the tooth out himself against Valhallen’s admonition to take him to the dentist as they have the tools to take the chip out properly.

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.

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.

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

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

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

Dexter and Dee Dee go to South America to catch the legendary chupacabra.

Dexter accidentally becomes Dee Dee’s foot when the two fuse together. Now, they have to wait 24 hours to reverse the fusion.

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

Since his studying is interrupting his favorite TV shows, Dexter creates a helmet to absorb the shows directly. However, the plan backfires when he randomly snaps into television-based outrages.

Dexter creates a new type of ink that lets him command people to do whatever he wants. However, when Mandark gets his hands on it, Dexter is the one that becomes commanded.

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

Dexter’s new device allows him to study for the next day’s French test while sleeping. It malfunctions, causing a single phrase (omelette du fromage) to repeat throughout the night, causing Dexter to wake up the next morning speaking nothing else except omelette du fromage.

Monkey must defend the city from a giant underground lava monster, Magmanamus (Brad Garrett), who cannot sleep because of the noise created by its residents.

Suspicious that Dee Dee has not entered his lab even once on a particular day, Dexter shrinks himself and enters her room to spy on her. He soon becomes an unwilling character in Dee Dee’s doll story, but he believes the story to be real.

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

Mandark’s sister Olga Astronomonov (a.k.a. Lalavava) tries to upstage Dee Dee at dance school.

Dee Dee’s new dance moves annoy Dexter to no end.

Dee Dee’s imaginary friend Koosalagoopagoop (Dom DeLuise) suddenly comes to life and starts annoying Dexter.

Dexter and Dee Dee’s secret decoder rings hold the keys to joining the Action Hanks and Pony Puff fan clubs respectively, but they interchange the clues by mistake, causing them to switch clubs.

When an intelligence test grades Dexter as “average”, he shuts down his lab and tries to live life like a normal kid.

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

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

While on a date with Agent Honeydew, Monkey gets hypnotized by the music of the Organ Grindor (Jim Cummings), who commands him to rob Fort Knox.

Dexter, Monkey, Agent Honeydew, the Justice Friends, Dee Dee, her imaginary friend Koosalagoopagoop, Mandark, his parents, and Dexter’s parents participate in a cross-country race a la Wacky Races.

Dexter finds a lost Labrador Retriever, but when he teaches the dog to speak human language, he turns out to be very annoying, prompting Dexter to find the dog’s owner.

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.