Dexter is trapped in his school by the janitor in revenge for making him work late everyday due to Dexter’s habit of leaving the school last everyday.

When Dee Dee tries to cut off a piece of her hair, she accidentally cuts off one of her pigtails. Dexter gives her a potion to make her missing hair grow back. However, Dee Dee squirts too much of it in her hair, and Dexter must return Dee Dee’s hair back to normal.

Dexter and Dee Dee enter tryouts to become Major Glory’s sidekick. When Dee Dee wins, Dexter realizes that fancy costumes are not the only criterion to become a superhero.

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

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.

Dexter decides to work with Mandark, but finds himself doing all of the work. In the end, Mandark tries to press the button when Dexter connects the plug in the outlet to bring his show title back.

Dee Dee’s father trains her to fight a gang of bicycle-riding rogues dressed as ninjas who target her paper route every morning.

When Dee Dee claims that anything can be hers because Dexter “doesn’t have his name on it”, he invents a label-making gun.

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.

Dexter calls upon the “shoe gnomes” to repair his shoes, but he seeks out Dee Dee to rid himself of them afterwards.

Peltra wants to turn Monkey into a fur coat.

Dexter finds out that all of Mandark’s plans are taken from a comic book.

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

Quackor returns to battle Monkey in Dexter’s Lab until Quackor lays an egg; then the two fall in love.

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

Monkey narrates a documentary of the future of laboratories and sciences.

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

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

Dexter creates a robot to assist him, but the robot starts controlling his lab and tries to destroy Dexter.

After a Puppet Pals marathon, Krunk dreams the Puppet Pals are attacking puppet versions of Major Glory and Valhallen.

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 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.

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.

Dexter’s father tries to get himself and Dexter to his fishing spot before sunrise so that they can start fishing before others arrive.