Dexter’s parents and Dee Dee have their minds taken over by an alien life form that escaped from Dexter’s lab.

Dee Dee goes and plays in her own “lab” after being kicked out of Dexter’s.

When Dee Dee takes photographs of his lab, Dexter goes on an adventure to retrieve the photos before his parents see them.

Dexter becomes the stern administrator of his local library.

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

Dexter finds the exact opposite of his family, a hyperactive boy who is like Dee Dee and has scientist parents who are like Dexter. Sensing to fit in, he switches places with the boy.

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

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.

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.

Dee Dee accidentally shuts down Dexter’s lab, and he has to power it back. In the process, Dee Dee attempts to keep Dexter from finding out what she really did.

When Dee Dee causes Dexter to mistakenly take a book from the library without checking it out, they sneak into the library at night to put it back.

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

Dexter tries to emulate the barbarian hero of his favorite comic book.

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

When Dexter gets amnesia, Dee Dee decides to play tricks on him by creating a whole new identity for him in her image.

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.

When Dexter is bitten by a clown’s dentures, he begins turning into a mad clown every night, terrorizing the town with his mayhem, and only Dee Dee, who knows mime, can stop him.

After a crime prevention talk at school, Dee Dee, Lee Lee, and Mee Mee become crime fighters, but they unintentionally end up being neighborhood criminals.

Mandark enters a surfing contest and tries to cheat his way to victory to win Dee Dee’s heart from another surfer.

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

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

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.

Dexter and Dee Dee’s father buys a video game for them to play, but the game sucks Dexter inside when he plugs in the cartridge, and it is up to Dee Dee to bring him out.

When Dexter’s computer gets laryngitis, Dexter must find a replacement voice.