Characters / Dexter's Laboratory — Major Characters

Dexter's Laboratory Main Character Index
Major Characters | Secondary Characters | Dial M For Monkey | Justice Friends

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Dexter

Left: Seasons 1 & 2. Right, seasons 3 & 4

Voiced by: Christine Cavanaugh (First two seasons, Ego Trip, and first five episodes of Season 3), Candi Milo (Remainder of Season 3 and Season 4), Jeff Bennett (his Future Badass self in Ego Trip and his superhero self in "Comic Relief"), Luis Alfonso Mendoza (Latin American Spanish dub, first voice, early Season 1 episodes), Yamil Atala (Latin American Spanish dub, second voice, all seasons, movies and specials), Sara Vivas (Castilian Spanish dub)

A scientific Child Prodigy boy genius who owns a secret lab in his house. Despite his high intelligence, Dexter often finds himself in many conflicts, from his backfired experiments to his ditzy older sister invading his lab and causing trouble.

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• Accent Upon The Wrong Syllable: "Dee-DEE, get out of my laBORatory!"
• The Ace: When it comes to science, of course. There was even an episode where one of his teachers clearly has the hots for him.
• Adorably Precocious Child: He's a Child Prodigy genius who owns a scientific lab, but he also often participates in the foolish behavior of his elder sister and his friends since he's still a kid.
• Aloof Big Brother: Inverted as he's actually younger than her, but his maturity level cements him as distant from his immature older sister Dee-Dee.
• Always Someone Better: Proves to be this to Mandark, especially by end of the latter's first appearance. Best shown in "Mandarker" where the two compete in a science fair. Mandark is an inconsolable mess still hung up on his destroyed lab and has to resort to supernatural methods because he can't come up with anything on his own, while Dexter effortlessly impresses the judges with one of his "scribbles" and has moved on from being forced to shut down his lab.
• Animals Hate Him: As seen in an episode when Dee-Dee tries to get him to play outside numerous times and animals constantly beat him up. At the end of the episode, when Dexter is finally able to relax outside, several animals, including a fish, jump out of nowhere onto Dexter in a Big Ball of Violence.
• Animal Motifs: Several episodes show that Dexter is normally associated with rabbits. In the pilot, DeeDee accidentally turned him into a bunny. In "Double Trouble", a running gag has a rabbit pop out of Dexter's lab coat. Lastly, Dexter wore bunny pajamas in "Critical Gas" and "Catch of the Day".
• Arch-Enemy: to Mandark. The two of them have a bitter rivalry.
• Art Evolution: In the post-movie seasons, Dexter becomes more square-shaped, with thinner arms, larger glasses, and only one button on his lab coat.
• Aside Glance: Has done these on occasions whenever he's annoyed by someone (usually Dee-Dee).
• Badass Bookworm: He is a tiny, stub-limbed boy genius who spends all his time in his secret laboratory, trying — in vain — to keep his pretty-princess Cloudcuckoolander sister out. Until a monster attacks the city, or aliens invade, or a meteor threatens Earth; then Dexter pulls out one of his giant, anime-inspired robots, super-powered exoskeleton suits, or space ships and kicks ass. He also seems to have learned kung-fu at some point.
• Berserk Button:
  • Do not enter his lab. Understandable, since the lab is a secret, and those who do so are either invaders (Mandark, and in one case, due to a case of mistaken identity, a U.S Army unit), or simply unwelcome (Dee Dee). He's a bit more understanding towards those who stumble across it by accident, such as his piano teacher, Ernie the Electrician, and a sleepwalking Dad, at least once he's done with the initial Freak Out.
  • He won't tolerate anyone breaking his glasses, either. In Ego Trip, Mandark breaking his glasses causes the wimpy young adult Dexter to stand up to him.
  • Trying to correct his opinions or disagreeing with his calculations infuriates him.
• Big Brother Instinct: Or little brother, in this case. Mess with his sister, and you're dead meat.
• Big Good: His elderly self "Ego Trip", having turned the world into a scientific utopia by sharing his genius with the rest of humanity using the Protocore. Also in any crossovers with other Cartoon Network franchises, he's either this or the de facto Leader including Cartoon Cartoon Fridays and FusionFall.
• Big Eater: Throughout the series, Dexter is often shown eating something. For instance, he sometimes eats a sandwich in various episodes. In one mini-short, Dexter had a dream where he was eating a pyramid made of hamburgers. In the episode Critical Gas, Dexter devoured a gigantic "Big Bad Burrito" in a mater of minutes.
• Big "NO!": He gives these out frequently when something bad happens to him or Dee Dee ruins something.
• Black Bead Eyes: Sometimes when seen without his glasses, depending on the episode. This is more common in the Savino era episodes than in the Tartakovsky era episodes.
• Brutal Honesty: Dexter tends to wear the truth on his sleeves, hurtful as it is.
• Butt-Monkey: Nothing goes right for this kid. Nothing. While little is known of his life between childhood and early adulthood, Ego Trip reveals that after the events of the series itself, he also had to deal with Mandark stealing his ideas, using them to basically institute a fascist dystopia, and torture him on a daily basis. At this point, his suffering is no longer Played for Laughs.
• Cain and Abel: Usually the prickly Abel to Dee Dee's oblivious Cain, but Dexter falls squarely into the former category when he and his future selves create a quintet of mechanized assassins to kill his sister as punishment for saving human civilization when he was just inches away from doing so himself.
• The Cameo: Dexter's and Dee Dee's names appear on Uncle Grandpa's list at the end of the Steven Universe / Uncle Grandpa crossover episode "Say Uncle".
• Can't Take Criticism: Dexter has a difficult time taking constructive criticism when one disagrees with his opinions and reacts with such pique.
• Character Catchphrase:
  • "Dee Dee, get out of my lab-OR-a-tory!"
  • "Ahh, what a fine day for science!"
  • "I am Dexter, Boy Genius!"
• The Chew Toy: He suffers this greatly in a lot of crazy forms. For example, his entire lab is completely destroyed, the earth is destroyed, Dexter is turned into a sandwich, etc. He also gets into big trouble from his mom and dad as well. Especially his backbone-lacking teenage/young adult self in "Ego Trip", who works for Mandark designing cubicles in the future.
• Child Prodigy: A self-described "boy genius" with his own hidden lab.
• Clock King: Dexter once bought an expensive popsicle and paid with pennies. When the ice cream man asked Dexter how long it took him to count the pennies, Dexter correctly answered the question.
• Cloudcuckoolander's Minder: He is quick to call Dee Dee out on her recklessness and stupidity.
• Create Your Own Villain: Dexter unintentionally did this to Mandark when he laughed at the latter's Embarrassing First Name, which happened to be "Susan."
• Crossdresser: Dexter has been dressed as a girl quite a few times throughout the series.
• Crouching Moron, Hidden Badass: Of a sort. Dexter tends to fail spectacularly at any form of physical activity, particularly sports... until the backdrop changes from "sports" to "Deedee let a giant monster out of the wormhole machine." Basically, he's an exaggerated stereotype of nerds are wimps up until science is involved, at which point he will physically go toe-to-toe with adults and give them a run for their money. He can also go from deflecting lasers with his wrench like a Jedi to slap-fighting his rival and somehow manages to be in character both times. Rule of Funny is involved, but still.
• Deadpan Snarker: Especially in his interactions with Dee Dee, he's prone to sarcastic remarks.
• Depending on the Writer: How smart, physically capable or socially savy he is can differ from episode to episode.
• Didn't Think This Through: One of his biggest flaws, and a side-effect of his massive ego, since he's convinced of his own brilliance and never considers that he could possibly fail or that he should include backup plans and failsafes.
  • In "Morning Stretch", he used a time-slowing helmet to turn thirty seconds into thirty minutes, allowing him the time to get ready for school. He failed to realize that the slowed time would prevent him from properly taking a shower or making breakfast, and his homework ignited from Friction Burn when he tried to finish it.
  • In "The Continuum of Cartoon Fools", he gets so desperate to keep Dee Dee out of his laboratory for good that he destroys all the secret entrances and locks the front door before swallowing the key, realizing too late that this would keep even himself from entering the lab.
  • In "Comic Stripper", when he realizes that Mandark is getting his latest Evil Plans from the comic book Mister Misery, he buys every copy of the next book in an effort to beat Mandark at his own game, expecting him to do the same. However, Dexter is caught unprepared when Mandark instead copies the comic book Dangerous Duck. It didn't occur to Dexter that since he bought all of the copies of Mister Misery, Mandark wouldn't be able to get the new issue and copy Mister Misery's moves; Mandark even lampshades it.
• Ditzy Genius: He fits the bill perfectly. Dexter can create time machines, sentient robots, and interdimensional portals, but in "Maternal Combat," he is utterly incapable of taking care of himself for a single day while his mom is sick. He doesn't know how to cook (having never heard of flour), and is is amazed at the sight of dust. Let's not forget that he's also gullible, and in the episode where he gets chicken pox, he literally has no idea what chicken pox is. In general, what he has in scientific smarts, he lacks in common sense. It's all Justified though, considering for all his intelligence, he's still just a kid.
• Earn Your Happy Ending: It takes a lot of hardship and more than a few decades, but Dexter's genius eventually makes the world a better (and smarter) place as Ego Trip shows.
• Emperor Scientist: He grows up to be an incredibly benevolent, if scatterbrained, elderly inventor who presides over a sublime Utopia.
• Enraged by Idiocy: Is easily angered by Dee-Dee's ditzy behavior.
• Extreme Doormat: His early 20's self in Ego Trip is this to Mandark.
• Eye Glasses: The glasses can change shape depending on expression.
• Fatal Flaw: Dexter has three that are almost always his downfall:
  • His temper. Dexter proves able to handle Dee Dee effortlessly when he takes a moment to think but he has a Hair-Trigger Temper that makes him default to impulsive action when it gets set off.
  • His pride. Dexter has a very high opinion of himself, disproportionate to his actual competence, which has caused him some major issues. Dee Dee can manipulate him into doing things by implying he isn't as smart as he holds himself to be and if he believes that someone is his superior in ways to deems meaningful then it tends to break Dexter. Badly.
  • His devotion to science. He will sometimes employ convoluted scientific methods to achieve his goals, often overlooking more simple solutions that would be less likely to blow up in his face.
• Fan Boy: He's a huge fan of street hero Action Hank and The Cape superhero Major Glory.
• Fiery Redhead: His family is split evenly between this and the Dumb Blonde stereotype; he and his mother are fiery redheads and his sister and dad are happy-go-lucky yellow-haired ditzes.
• The Finicky One: He's remarkably fastidious about his personal hygeine (but not quite on the level of his intensely germophobic mother). He's also a very picky eater.
• Foolish Sibling, Responsible Sibling: The Responsible to Dee Dee's Foolish. Dexter is quick to impart logic into the latter, who is a complete scatterbrain.
• For Science!: His catchphrase is dedicated to his appreciation for science.
• Future Badass: Invoked in the Made-for-TV Movie, Ego Trip, wherein Dexter travels to the future for the primary purpose of seeing what kind of badass he is. In the dystopian future version of himself, he comes to resemble his hero Action Hank: big, brawny, and bearded (and unlike Hank, he goes bald), and his Mad Scientist pseudo-Germanic accent is replaced by an Arnold impression.
• Future Loser: This trope is also averted in Dexter's other two future versions, a wimpy office drone and a hilarious old man. The Future Badass version of Dexter exists between the two chronologically. However, we eventually see the former take a level in badass.
• Gadgeteer Genius: Dexter created a lot of science inventions in the series.
• Gleeful and Grumpy Pairing: The irritable Grumpy to Dee Dee's gleeful Genki Girl.
• Good Is Not Nice: He's an egotistical jerk, but undeniably a good person. Case in point: when he thinks he's dying, his to-do list includes doing nice things for his family, finishing his chores, and ending war and hunger.
• Grade Skipper: In one episode, Dexter was considered for grade-skipping but needed to improve his P.E. grades. He cheated his way into victory and ended up becoming Dee Dee's yearmate.
• Gym Class Hell: A firm believer in this trope, and goes to extreme lengths to avoid it, including a false excuse note. As shown in the dodgeball episode, he's entirerly correct.
• Hair-Trigger Temper: Dexter is rather temperamental, mainly due to his big ego and annoying sister.
• Height Angst: In "Ewww, That's Growth", Dexter and his family want to go on a really big rollercoaster, but Dexter is denied due to being too short. The resulting angst drives him to become as tall as possible, eventually allowing him to finally go on the rollercoaster by the end of the episode. This backfires when he becomes so tall that he hits the ceiling at the very end.
• Herr Doktor: Dexter is a Mad Scientist with a (possibly?) German accent — made more blatant (and funny) since none of his family has any accent or gives any indication they have any German ancestry.
• Hoist by His Own Petard: He sometimes suffers when his inventions malfunction at the wrong time, or work against him because he didn't think things through.
• Identical Grandson: He's a younger version of his grandfather.
• Idiot Ball: He can time travel and build an underground lab miles long but will go through hell and back to buy ice cream that he could easily make at home.
• Improbable Weapon User: He's pretty handy with a wrench in matters of melee combat as well as mechanics.
• Innocent Prodigy: In one episode he sees a repair-man working on the house's electrical system, and after some failed attempts to find out what he's up to using technology, Dexter's Plan C turns out to be to run off to "mommy" and ask her who's the strange man messing around with the fuse box. In another, he treats a burnt out light bulb as a kid would the death of a beloved pet.
• Insufferable Genius: He can be very arrogant when it comes to his smarts and has little tolerance for any criticism of his work.
• I Just Want to Be Badass: Despite his impressive accomplishments, he often yearns to be the same kind of badass as his heroes Action Hank and Major Glory. He eventually succeeds as seen in Ego Trip.
• Jerk with a Heart of Gold: He's not a bad person, but he can be quite rude, condescending, and egotistical.
• Large Ham: He can be quite expressive and loud, especially when he yells at his sister to get out of his laboratory or is gloating about his latest scientific achievement.
• Like Parent, Like Child: He's a Fiery Redhead like his mother. She is also the source of his boundless pride and creative impulses.
• Machine Worship: It's implied at many times that Dexter actually has a reverence for technology and science on a religious level. During Ego Trip, the Dexters from various time points all prayed to a deactivated Computer before getting to work and Dexter had once referred to notable past scientists in as "Disciples of Science" in Star Spangled Sidekicks. Not to mention his personal relationship with his Computer which he referred to as "his one true love".
• Mad Scientist: Not villainous example, obviously. The premise of the show is that Dexter is a kid mad scientist with a secret laboratory.
• Manchild: Teenager Dexter from "Babysitter Blues" and Old Dexter from "Old Man Dexter" could be excused on the grounds that both circumstances had Dexter accelerate his age to woo his sitter and watch the late night movie with his family respectively, but Future Badass Dexter cements it by whining he should've been the one to save the future and goes on with the plan of creating robots to destroy Dee Dee.
• Manly Facial Hair: One of his future selves in Ego Trip is very muscular, has a beard, and is bald.
• Mature Younger Sibling: Dexter plays the Only Sane Man role to his ditzy older sister Dee Dee.
• Naked People Are Funny: Has an unfortunate tendency to lose his clothes during the hijinx of the episode, with his crotch being covered by a leaf.
• The Napoleon: He has the short stature and the attitude.
• Narcissist: He has a very high opinion of himself. Case in point: in "The Parrot Trap", he built a robotic parrot purely so he could hear it repeat his own self-indulgent praises. The entirety of Ego Trip happened because Dexter couldn't fathom the idea that he didn't save the world, Dee Dee did.
• Never My Fault: Never accepts responsibility whenever one of his inventions backfire, especially not when it's due to his own oversight. In one episode, he boosted Dee-Dee's intelligence for the sole purpose of having a Yes-Man around and quickly grew furious when she pointed out his mistakes.
• Nerd Action Hero: He has his moments in the show, being a super scientist with an assortment of cool robots and gadgets, but it really becomes true for his Future Badass version seen in Ego Trip.
• Nerd Glasses: He has thick framed glasses that double as Eye Glasses.
• Nerds Are Naïve: Dexter may be a Child Prodigy but he also has a seriously limited grasp on what girls are like. He often laments about his sister Dee Dee's "cooties", treating them as if they were an infectious disease. One episode ("Tribe Called Girl") had him infiltrating Dee Dee and her friends' slumber party like he was studying wildlife.
• Nerds Love Tough Schoolwork: Looks forward to hard tests.
• No Full Name Given: His family surname is never revealed.
• No-Respect Guy: He's Surrounded by Idiots and hardly gets any respect.
• No Social Skills: In most cases, he has trouble understanding how to talk to kids his age as well as basic concepts; for example, in different episodes, he has no idea what flour and chicken pox are. This tends to vary from episode to episode, in some instances he is much better socially-adjusted than others.
• Not So Above It All: Dexter often participates in the foolishness of not only Dee-Dee (like letting Dee-Dee run around his laboratory with scissors, but after putting her in Powered Armor first), but also the other kids his age. Justified, considering that despite him being more intelligent than his peers, he is still a child and therefore has the same desires as many other kiddos.
• Older Than They Look: According to the "Love According to Dexter" song, he's 8 years of age.
• Omnidisciplinary Scientist: It may be easier to look for what areas of science Dexter HASN'T covered throughout the show.
• Only Sane Man: Occasionally, especially when he's with his nuthouse family, he's the only one with any common sense.
• O.O.C. Is Serious Business: One of the bumps features him catching Dee Dee running with scissors. Rather than simply yelling at her to get out of his lab, he instead stops her and calmly but urgently explains the dangers of what she was doing. The fact that Dee Dee actually seems to take his lecture seriously indicates that even she realized it must be bad if Dexter forgoes his usual kicking her out to actually warn her of the danger instead.
• Ping Pong Naïveté: He had his moments of stupidity. One example is when he thought he was going to die...because he had gas. We're talking about a boy genius that has done everything from go inside his sister's body to traveling to other planets using his inventions. To "simulate" the gas buildup in his lab, he used a balloon to represent himself. In other episodes/shorts, he didn't know what the "strange protrusions" all over his body were (he had the chicken pox) and tried to do a search through the entire animal kingdom for the "species" known as... the girl.
• Pint-Sized Kid: Is implied to be in his pre-teens, but is so pint-sized he could literally fit in a giant's hand.
• Plot-Sensitive Snooping Skills: Despite all the tests he put Monkey through after giving him super powers, he failed to notice any changes.
• Protagonist Title: He is the show's main character, and his name is featured in the show's title.
• Precocious Crush: On Lisa, the babysitter.
• Ridiculously Successful Future Self: His elderly future self is the ruler of a utopia.
• Rubber Man: Becomes one in Now That's a Stretch! by taking some bubblegum from Dee-Dee and merging with it. This soon comes to bite him in the ass, however, as Dee-Dee finds him to be a way more fun bubblegum than the old one...
• Savvy Guy, Energetic Girl: Savvy Guy to Dee Dee's Energetic Girl. Dexter is book-smart while Dee Dee is an utterly ditzy scatterbrain.
• Science Hero: He is a Child Prodigy who owns a huge underground laboratory.

• Shorter Means Smarter: Not so much when paired with his much taller rival Mandark, but definitely when paired with his taller sister Dee Dee.
• The Short Guy with Glasses: He's two feet tall.
• Small Name, Big Ego: Became one in later seasons due to Flanderization.
• The Smart Guy: Of the Child Prodigy variety.
• Smart People Know Latin: Or take it, anyway. In "Accent You Hate" he's shown opening his locker and saying "Good morning" to his Latin and math textbooks.
• Smart People Wear Glasses: He's a Child Prodigy genius and wears Nerd Glasses to showcase that.
• Spock Speak: He uses lots of big words, has a rather monotone voice and uses little to no contractions in his everyday speech. How strong his spock speak is often fluctuates between episodes, however.
• Straight Man: He plays this role to Dee Dee in that Dexter's second-most defining characteristic after being an Insufferable Genius is offering rationality to her.
• Swiss-Cheese Security: No matter what measures he takes, Dee Dee always manages to slip into his laboratory without any trouble.
• Teacher's Pet: He's this to the point where his teacher blew a kiss at him once,although Mandark gives him some competition.
• Throw the Dog a Bone: Ego Trip, as the title implies, is basically an entire movie of Dexter finding out that all his efforts pay off...eventually.
• Took a Level in Badass: In "Ego Trip". Young adult Dexter is portrayed as a complete wuss. Until Mandark breaks his glasses.
• Trademark Favorite Food: In D&DD, he grabs a Pixie Stick, and happily calls it his favorite candy.
• TV Genius: He's a world renowned genius capable of building time machines, giant robots and create all sort of genetically modified creatures, yet thinks "girl" is some kind of tribe, doesn't know what dirt is, and one time thought he was going to die due to having gas.
• Unexplained Accent: It's never explained why Dexter has an Eastern European accent (?) despite the fact that the rest of his family members have a mixture of American accents. Possibly a meta-Author Avatar related reason: Tartakovsky was born in the Soviet Union and moved to the United States as a child, so he most likely had a similar accent at one point.
• The Un-Favourite: His parents usually love him and his sister Dee Dee equally, but one notable instance of this trope is in "Oh, Brother", where Dexter turning his sister Dee Dee into a brother named Doo Dee resulted in Doo Dee getting all the attention while Mom and Dad ignored Dexter.
• Ungrateful Bastard: In "Misplaced in Space", he refuses to thank Dee Dee for rescuing him from the alien planet. Considering her constant button pushing is the reason he ended up there in the first place, however, it's easy to see why.
• What the Hell Is That Accent?: Dexter has a very peculiar accent that is either aiming for a stereotypical Eastern European accent, or a Bulgarian accent. Even Genndy Tartakovsky isn't certain what his accent is supposed to be.
• The Wonka: Zig-zagged. Sometimes he has ideas which can work really well, like the Neurotomic Protocore or, a self-driving car, but other times, his ideas have failed due to poor execution or social naivete. Played for Drama in that he's bullied at his school for being this type of kid.
• World-Healing Wave: The purpose of the Neurotomic Protocore is to send out such a phenomenon which would boost the joint intellect of mankind to superhuman levels, eliminating ignorance and promoting universal peace & brotherhood. It can also do the exact opposite, sucking in the intelligence of human beings worldwide to solely enrich the mind of its user, which is why Mandark wanted it so bad. However, while Dexter was able to create the core itself when he was just a child, it would be decades until he or Mandark would find a way to actually tap into its power.
• Would Hit a Girl: He and Dee Dee have fist-fought each other on multiple occasions.

Dee Dee

Dee-Dee in season 1

Seasons 3-4

Voiced by: Alison Moore (Season 1 & 3), Kathryn Cressida (Season 2 & 4), Kevin Michael Richardson (deepened voice in "Dee Dee Be Deep"), Pamela Adlon (gender-bent self Doo Dee in "Oh, Brother"), Cristina Cavalinhos (European Portuguese dub)

Dexter's elder sister, who tends to behave as though she's much younger. She's a ditzy Dumb Blonde and Cloudcuckoolander who often finds herself invading her brother's laboratory and messing with his inventions, often to a fatal fault.

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• Accidental Hero: At the end of Ego Trip when she pressed the button that reversed the effects of the neurotomic protocore that Mandark used to make everyone idiots, much to the ire of the Dexters.
• Action Girl: She doesn't show it all too often, but when she has to (usually when Dexter is in danger), she can be a certified One-Woman Army, as evidenced by her rescue of him from an alien jail.
• Adaptational Attractiveness: In the 2009 computer game FusionFall, Dee Dee is depicted in a more mature artsyle.
• All Girls Like Ponies: She is a pony fancier, as are her cloney best friends. There was the episode where she asked Dexter to turn her into a pony because she liked the My Little Pony expy so much.
• Annoying Younger Sibling: Inverted. She's actually an "Annoying Older Sibling" to Dexter, constantly breaking his stuff among other things.
• Bare Midriffs Are Feminine: She's a ditzy teenage girl who wears an outfit that shows her belly in "Sassy Come Home".
• The Bad Guy Wins: There are several episodes that end with her getting her way and Dexter suffering in someway, usually with his lab being wrecked or completely destroyed by her. To list a few examples:
  • In "Dexter's Assistant" she becomes a genius that's smarter than Dexter, and after she quits being his assistant she wins the science fair he enters.
  • In "Game Over" she successfully defeats Master Computer and saves Dexter and his lab. But instead of getting him out of his computer she inserts a new game and starts beating him up, on the grounds he can no longer get mad if she beats him at games.
  • In "Monstory" she and Dexter both become monsters and she tries to tell him a long and annoying story. They eventually fight and Dee Dee wins, pinning Dexter down so she can finish and force him to listen. It turns out her story was just a long knock knock joke, which she said early it wasn't.
  • "Trick Or Treehouse" has her trap Dexter in her treehouse after he spent the whole episode wondering what she was doing in a tree. Since he broke into her treehouse she decides to go have fun in his lab and the episode ends with the sounds of her destroying Dexter's lab as he begs her to come back.
• Berserk Button:
  • When Dexter wouldn't listen to her long-winded story about her day, she burst into tears, turned into a giant monster and went on a rampage.
  • She gets furious when Dexter uses one of her dolls as an experiment.
  • When Dexter "fires" Dee Dee in "Dee Dee and the Man", she got seriously outraged by this and got kicked out to her room.
• Beware the Nice Ones: Dee Dee is quite a force to be reckoned with if angered.
• Beware the Silly Ones: God help you if you make Dee Dee seriously angry.
• Big Ol' Eyebrows: Dee Dee's design in Season 1 often consisted of thick black eyebrows.
• Big Sister Bully: Her treatment of Dexter treads the line between Innocently Insensitive horseplay and callously asserting her own wants at his expense. In "Golden Diskette", she steals Dexter's money right out of his hands to buy something, and when Dexter asks why she did so, she tells him point-blank, "You're so small and weak that I could!"
• Big Sister Instinct: Mess with her brother, and you're dead meat. Despite coming off as a pain in the neck to him, Dee-Dee loves her younger brother and has acted protective towards him on numerous occasions.
• Bitch in Sheep's Clothing: Her sugary, cheerful exterior can hide one hell of a mean streak. In addition to her constantly destroying Dexter's lab for no reason other than to amuse herself, she constantly mocks him about his size and even in one episode, while posing as their mother, says that she's prettier, taller, and way more popular than he'll ever be. How their parents never pick up on this behavior is anyone's guess.
• Born Lucky: In contrast to Dexter, almost EVERYTHING turns out great for her, from winning a $200 million-dollar check to beating Dexter at every game they play to being picked as Major Glory's sidekick. And these are just a few things.
• Brainless Beauty: She's a beautiful girl (at least according to Mandark), but a rather dumb one.
• Break the Cutie: In "Down in the Dumps", when Mr. Fuzzums got taken away by a garbage man and thrown into the city dump, Dee Dee got insanely depressed when this happens. Then in "Folly Calls", she accidentally cuts off one of her pigtails and starts screaming and running around because of her messing up her hair. Then she tries to glue it back on, but it just slips right off.
• The Cameo: Dexter's and Dee Dee's names appear on Uncle Grandpa's list at the end of the Steven Universe / Uncle Grandpa crossover episode "Say Uncle".
• Character Catchphrase: "Oooooh, what does *this* button do?" The unfortunate answer is, more often than not, "cause some sort of catastrophic disaster in the Lab".
• Cheerful Child: Dee-Dee holds a very sunny disposition on life.
• Cloudcuckoolander: She is born in Cuckooland. It is especially evident when she tells Dexter her bedtime story while she's sick, mixing a variety of common childhood nursery rhymes and stories.
• Childish Older Sibling: She acts far more as an Annoying Younger Sibling to Dexter despite being older.
• Constantly Curious: With frequent invasion of Dexter's privacy comes great curiosity from Dee-Dee.
• Crouching Moron, Hidden Badass: While Dee Dee is very ditzy, she's actually capable of taking on serious threats that Dexter is too weak to fight without his inventions.
• The Cuckoolander Was Right: In "Chicken Scratch", she is shown to be right about scratching chicken pox causing one to turn into an evil contaminated chicken.
• Cuckoosnarker: Dee-Dee is prone to delivery of witty banter in her more self-conscious moments.
• The Cutie: A bubbly, ditzy, lovable little girl who wears pink.
• Curious as a Monkey: Dee-Dee is very amused by Dexter's scientific inventions, expressing constant curiosity to their use.
• Cute Clumsy Girl: Tends to be quite clumsy.
• Damsel in Distress: Has a tendency to get herself in trouble and needing Dexter to bail her out, though it's not always her fault, such as being held captive by Jojo, an interdimensional monster Mandark released.
• A Day in the Limelight: In the online game Dee Dee's Moon Squad, Dexter sends her and her friends to the moon so they won't mess up his lab, and she has to pilot a moon buggy across ten levels to reach the spaceship he's provided so they can get home.
• Deadpan Snarker: When she's not being a ditz, tends to snark.
• Depending on the Writer: Her intelligence and disposition towards Dexter fluctuate wildly from episode to episode. In some episodes, she's rather innocent and her destructive tendencies are accidental and due to playful clumsiness, and she only bothers Dexter because she wants his attention; in others, she's far more malicious and intentionally antagonistic, acting as a Big Sister Bully who messes with Dexter because she can. In some episodes she's a Genius Ditz who acts as a Straight Man to the more naive and impressionable Dexter; in others, she's barely literate and dim-witted even by ordinary standards.
• Disappointing Older Sibling: Her younger brother is a Child Prodigy who is frustrated with having such a ditzy sister and sees her as a nuisance.
• The Ditz: The trope namer for What Does This Button Do?. She often annoys Dexter because of her idiocy.
• Dreadful Musician: She has an absolutely terrible singing voice. Doesn't stop her, though.
• Dumb Blonde: A mix of this and Cloudcuckoolander... though she still has her moments of brilliance.
• Dumb Is Good: She's incredibly naive, but much more cheerful and pleasant than Dexter.
• Early Installment Character-Design Difference: Had thick eyebrows and seemed to lack a chin in early episodes.
• Easily Forgiven: Even after destroying his lab in his first appearance, Mandark still continues to crush on Dee Dee in episodes after that.
• Feminine Mother, Tomboyish Daughter: Inverted with her and Mom.
• The Fool: Her moronic actions tend to go unpunished.
• Foolish Sibling, Responsible Sibling: The Foolish to Dexter's Responsible. Dee Dee is incredibly silly and naive, while Dexter is sophisticated and rational.
• Fun Personified: Dee-Dee rarely has a serious bone in her body and puts the fun in everything.
• Genius Ditz:
  • She gives a somewhat accurate description of Gregor Mendel in the Sasquatch episode. She can break through any security measure Dexter comes up with. When she's not wrecking them, can use Dexter's inventions with instant mastery, like a hovercraft Dexter himself crashed or an incredibly complicated giant mech.
  • A subtle moment from the show's opening titles implies that Dee Dee is smarter than she lets on: Dexter frantically presses a button, attempting to turn on a large light, then Dee Dee briefly gives Dexter an aside glance and coy smile and plugs a cord into a nearby socket, successfully turning on the light.
• Genki Girl: She's an extremely energetic, hyperactive girl.
• Girlish Pigtails: She wears her hair in high pigtails, fitting with her generally girly personality and interests.
• Girls Love Stuffed Animals: She loves her dolls.
• Girly Girl with a Tomboy Streak: She likes playing with dolls and ballet, and has a stereotypical girly attitude, but she also likes video games, sports and rollerskating.
• Gleeful and Grumpy Pairing: The gleeful Genki Girl to Dexter's irritable Grumpy.
• Hair of Gold, Heart of Gold: A blonde girl who loves her little brother to no end.
• Hypocritical Humor: Whenever Dee Dee meets someone of her own clingy and destructive level, she finds them as intolerable and inconsiderate as Dexter finds her. For example, in the pilot episode, when she finds out that Dexter broke into her room to steal one of her dolls for experiments, she completely loses it and confronts him, while ignoring the fact that she regularly breaks into his lab uninvited and destroys it without a care for Dexter's feelings. Then we have Dollhouse Drama, in which she steals one of his miniatures, brings it back to her room, and plays with it.
• Idiot Houdini: Dee Dee always made a huge mess of Dexter's lab through her sheer idiocy, sometimes even causing quite a lot of destruction among others as well, yet she almost never got any repercussion for it. Seasons 3 and 4 were a little better about averting this. Partly because there were fewer episodes that had Dee Dee in the lab but she was a lot more prone to actually getting called out for her antics. It helps that there were times that she actually did try to clean up the messes she made and that she either went down with Dexter or suffered as a result of her own actions.
• The Ingenue: With an inability to detect malice and very naive nature, Dee-Dee causes wreaks lots of havoc.
• Innocent Blue Eyes: She has blue eyes and is definitely naive.
• Innocently Insensitive: Dee Dee is usually just a playful Genki Girl who wants to play with her little brother. However her notions of fun include playing around with his pretty-looking (and somewhat delicate) toys, and no amount of ranting at her to leave him alone ever seems to faze her.
• Jerkass Ball: She holds several of these moments where she acts more downright malicious than Innocently Insensitive.
• Karma Houdini Warranty: There are episodes where she gets her comeuppance.
• Karmic Butt-Monkey: Against all odds, Dee Dee manages to be this in quite a few episodes. Sometimes, her trail of destruction is so extreme and disproportionate that it's next-to-impossible to justify, even when Dexter's ego and narcissism are taken into consideration, especially because, despite such personality flaws, Dexter wants to use his talents to change the world for the better. This makes the very few moments where Dee Dee gets punished all the more satisfying.
• Kiddie Kid: Dee Dee is elder to her titular brother, but tends to behave as if she were younger than him.
• Kindhearted Simpleton: Dee Dee is just as kind as she is ditzy.
• Knight Templar Big Brother: Dee Dee may appear to be a flake, but you do NOT harm her little brother. Or she will kick your ass.
• Leitmotif: This whimsical, piano piece that plays when she shows up, usually when dancing.^note Simulated here.
• Lethally Stupid: She usually sabotages Dexter's experiments and destroys his lab, although she does so out of ignorant curiosity rather than malicious intent.
• Like Parent, Like Child: Her dad is where she gets her lack of foresight and curiosity.
• Literal-Minded: In "Maternal Combat", Dee Dee cooks a mud pie, with actual mud!
• Little Miss Snarker: She tends to be sarcastic whenever she's not acting stupid.
• Lying Finger Cross: In the comic book story "Salt and Pepper", Dexter and Dee Dee make a deal where she'll stay away from his lab forever. When he tries to collect, she reveals that she crossed her fingers.
• Motor Mouth: She quite often speaks very rapidly, just barely able to be coherent without speaking slowly.
• My God, What Have I Done?: Dee Dee horrifyingly reacts as Dexter wrecks his own lab— and it all started with her trying to get Dexter to lighten up a bit.
  Dee Dee: (slaps Dexter in the face, snapping him out of it) Stop it, Dexter! Look at yourself! You're a monster! No longer the quiet creator but a mad destroyer! I'm so sorry. I shouldn't have pushed you. I know now it wasn't my place to try to change you. Oh, Dexter, please forgive me. Oh, what have I done??? (runs out of the lab, sobbing)
• Nice Girl: She's pretty darn sweet and she absolutely adores her little brother. Her destructive tendencies are usually due to clumsiness or carelessness rather than malice, and sometimes it's shown that the reason she's always sneaking into Dexter's laboratory is because she just wants to spend time with her brother.
• No Full Name Given: Her and Dexter's family name is never revealed.
• No Indoor Voice: She frequently yells at the top of her lungs.
• No Sense of Personal Space: Pretty much the defining premise of Dee Dee's character. It's rare for her to leave her brother alone.
• Not Helping Your Case: Even though Dexter turned out to be wrong about the possibilty that Dee-Dee would take advantage of being punished by being placed in Dexter's room so she could wreck his lab in The Old Switcharooms, the fact that she responded to her punishment by squealing with delight didn't do much to fix his paranoia.
• Oblivious to Love: Mandark is in love with her but she seems unaware of it.
• Our Mermaids Are Different: Dee Dee pretended to be a Mermaid swimming in the sea in "Ocean Commotion" episode.
• Person of Mass Destruction: Every time Dee Dee manages to get into Dexter's lab, she almost always leaves a massive amount of destroyed machinery and inventions in her wake. In Mandark's debut episode, Dexter even used this to his advantage to get back at Mandark.
• Pet the Dog: She may constantly be wrecking Dexter's stuff and annoying him to no end, but it is shown on more than one occasion that she actually does care about her younger brother.
• Pink Means Feminine: Along with her two friends, who wear the same clothes as her.
• Prefers Going Barefoot: She spent nearly the entirety of "Sassy Come Home" proudly running around barefoot after she took off her "goshforsaken boots", which attracted a new playmate - Sasquatch.
• "The Reason You Suck" Speech: She gives after Dexter yells at her and calls her stupid.

  Dee Dee: I feel sorry for you, Dexter. You're like a pickle— cold, sour and all bottled up in your laboratory. Toiling away alone in the dark, searching for answers to questions nobody asked. Locked away from the world, never to experience the true mysteries of life. Well, you can keep your cold, sterile little lab, because for me, the world is my laboratory. Goodbye Dexter, I'll never bother you again. (Dee Dee leaves, leaving Dexter alone in his silent, tomb-like laboratory.)

• Repetitive Name: Dee Dee.
• Savvy Guy, Energetic Girl: Energetic Girl to Dexter's Savvy Guy. Dee Dee is an extremely cheerful Genki Girl, while Dexter is a Child Prodigy.
• Shoe Size Angst: She has abnormally large feet. They're much bigger than the other members of her family, especially her mom. This is emphasized in the episodes "Sassy Come Home" and "Shoo, Shoe Gnomes".
• Smart Ball: Depending on the Writer, Dee Dee can be as dumb as a brick in some episodes, and absurdly savvy and able to predict Dexter's every move or even manipulate his own super science and security systems to her advantage. How capable she is comes down to a per-episode basis.
• Smarter Than You Look: It's implied more than a few times that Dee-Dee only acts goofy for the fun of it and has more awareness of what's going on than we think.
• Spanner in the Works: Especially in Ego Trip, when she wanders through the time portal at the end of the movie, goes "Oooh, what does this button do?", then pushes it and leaves.
• Squee: She tends to do this constantly.
• Sweet Tooth: She loves candy.
• The Thing That Would Not Leave: She frequently refuses to respect Dexter's privacy and constantly invades his lab.
• Tomboy and Girly Girl: Girly Girl to Mom's Tomboy.
• The Troublemaker: Dee Dee is constantly sneaking into his brother's secret laboratory, annoying him and disrupting his experiments, as well as destroying his equipment with her rambunctiousness.
• Unsportsmanlike Gloating: Whenever she beats Dexter in a game, she will always taunt him for it. In "Game Over", for example, every time Dee Dee beats Dexter at video games, she relentlessly rubs it in his face, dancing around the room and chanting "I won!". And when Dexter tells her he doesn't want to play with her anymore, she calls him a Sore Loser.
• Walking Disaster Area: At least whenever she's in Dexter or Mandark's lab. Or being abducted by aliens. Otherwise she manages to keep the property damage to a minimum.
• What Does This Button Do?: The Trope Namer. Dee Dee elevated this to an art form, as this would usually be the last thing Dexter would hear before one of his inventions goes awry. She sort of Lampshaded it in the episode where Dexter's trying to sleep:
  Dee Dee: I went into your lab... and, I pushed this button...
  Dexter: Oh, just like the last thousand times?
  Dee Dee: I think it's really serious this time... (cut to self-destruct device counting down)

Mom

Voiced by: Kath Soucie

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• '70s Hair: With some carry over from the 60s, in a flashback from "Snowdown" she wore her hair in a grown out bouffant (teased at the crown) that was down her back when she snowballed Dad in college.
• '80s Hair: The flashback episode "Glove at First Sight" showed Mom dressed as a Valley Girl with a side of Material Girl which included a side ponytail and fluffy bangs. For the big New Years Eve dance, she wears her hair in a asymetrical bob that Molly Ringwald would have favored.
• '90s Hair: Her mid-century housewife appearance is updated with an attractive and low-maintenance bob that Meg Ryan would have favored during the time of the show's premiere.
• Action Mom: Demonstrated in "Mom and Jerry", "World's Greatest Mom" and "A Mom Cartoon".
• Amazingly Embarrassing Parents: Most notably in the episode "Chess Mom", where she embarrasses her son while trying to cheer him on at the chess tournament.
• Berserk Button:
  • As seen in "Dexter's Rude Removal", the most Mom ever got beyond angry was when the rude clones of Dexter and Deedee not only made a huge mess of her kitchen during a food fight but used profanity as well.
  • Talking back to her, as Dexter learned in the episode "Dexter is Dirty".
  • Germs, period.
• Beware the Nice Ones: Whenever her Berserk Button is pushed, or her children are threatened.
• Cute Bruiser: Dexter's mother has shown to be able to fight very well.
• Fiery Redhead: The family is split evenly between this and the Dumb Blonde stereotype; Dexter and his mother are fiery redheads, his sister and dad are happy-go-lucky yellow-haired ditzes.
• Feminine Mother, Tomboyish Daughter: Inverted with her and Dee Dee.
• Flanderization: Her Neat Freak tendencies get played up considerably in the later episodes.
• Genius Ditz: Similarly to Dexter's dad. She shows frightening proficiency with technology when it comes to battling germs, but has also had several moments of stupidity.

• Hartman Hips: To the point where she currently provides the trope image. As shown in the episode Sister Mom, when Dee Dee gets turned into a duplicate of Mom in that episode, she feels her hips with awe. Exaggerated when Dexter is later seen using her butt as a seat when they're riding a bike.
• Housewife: She seemed to have little characterization outside of her housework, though it's been implied a few times that she was a lot more rebellious in her youth. Her typical outfit that she wore everywhere even included yellow rubber dishwashing gloves and an apron.
• Iconic Item: Her yellow rubber gloves. So much so that she feels naked without them.
• Like Parent, Like Child: Her kitchen is as important to her as Dexter's laboratory is to him, and when Dad starts horsing around in there it earns him a "GET OUT OF MY KITCHEN".
• Mad Scientist's Beautiful Daughter: Inverted. She’s the mad scientist’s beautiful mother. Pretty, prim, demure, and totally oblivious to the extent of her son’s genius.
• Male Gaze: Cameras don't hesitate to get as many shots from the back as they can. "Better Off Wet" in particular features her in a bikini.
• Mama Bear: Best shown in "Go, Dexter Family! Go!", where hearing her son cry for help motivates her into breaking free from her bonds and kicking the aliens' asses.
• Mistaken for Badass: She once "defeated" the reigning snowball champion (Dexter's dad) by playfully chucking a snowball at him. He's been convinced ever since that she has evil snowball powers, which she passed on to Dee-Dee.
• Neat Freak: The episode "Pslyghtly Psycho" suggests that she is actually germophobic, particularly when her gloves and slippers are removed and she finds herself afraid to even set foot on the carpet without them. This is outright confirmed in the episode "Glove at First Sight", which focuses on how she met Dad during her treatment for her fear of germs.
• Parental Obliviousness: It's amazing how she, along with Dad haven't figured out that the lab exists. This is partly explained by Dexter wiping their memories, but they only ever seem to find out when Dexter accidentally tells them himself.
• Redhead In Green: She wears a pale green blouse-shirt with a wide collar, white apron and dark green pants. Also her bikini is green.
• Skewed Priorities: She favors cleanliness over anything. One episode has her ignoring the fact Dexter had destroyed her entire house over the fact he was clean.
• Tomboy and Girly Girl: Tomboy to Dee Dee's Girly Girl.
• Unnamed Parent: She's only ever referred to as "Mom" — though her maiden name is probably "O'Reilly," given that in one of the later episodes, her brother visits the family and his last name is "O'Reilly."

Dad

Voiced by: Jeff Bennett

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• '50s Hair: As standard for his Standard '50s Father appearance, he wears his hair in a conservative cut that Ronald Reagan would have favored.
• '70s Hair: In his college flashback in "Snowdown", he is shown with shoulder-length hair with long sideburns and fuller bangs.
• '80s Hair: "Glove at First Sight" shows him with a mullet with hair down his neck and bangs that stand out.
• Abusive Parents: Downplayed, as he isn't horribly abusive, but as shown in several episodes, such as "Better Off Wet", Dexter's dad can be a bully, embarrassing and pulling childish pranks on his family for his own enjoyment. These often include pushing his family in the pool, and very manipulative behavior.
• Amazingly Embarrassing Parents: Has a tendency to humiliate his kids on accident.
• Art Evolution: His appearance after the reboot has the biggest redesign of all the characters, with him having a different shade of blonde hair, being a lot skinnier, and has a larger head.
• Berserk Button: You can threaten him, you can break his car and he'll just brush it off. But don't ever not-hold a door open for a lady—ESPECIALLY his wife!
• Beware the Nice Ones: There's his Manipulative Bastard tendancies, for a start. Then there's the times he gets really mad...
• Bumbling Dad: Both parents are bumbling, though their primary flaw was being clueless to Dexter's laboratory (and he has a memory erasing gun, so its more like they look stupid by comparison to their supergenius son). Dexter's father turns out to be a stunt biker when his job is finally revealed (up to then, he left every day dressed for an office job), making him much cooler than the typical example.
• Crouching Moron, Hidden Badass: He is often a ditzy Bumbling Dad who can be oblivious to his surroundings or what is going on, but if you dare to push a certain button with him, he will get serious. And when it happens, watch out.
• Dumb Blonde: In the Chubby Cheese episode when Dexter clearly stated he did not enjoy the pizzeria while Dee Dee did, his father responded "Well, it sounds like you kids are having a great time!". In the episode where Dexter illigally pirates cable for him, his father is repeatedly warned by the police that pirataton of their cable is a felony and he is doing illegal activity, and he just thinks they are trying to sell him cable. When Dexter gave a dog the ability to talk, his father failed to notice it even when it spoke right to him. Along with his wife, he mistook a T-Rex for a dog in one episode.
• Dumbass Has a Point: He may be a Bumbling Dad but every now and again, he'll give Dexter and Dee-Dee some good advice, such as when he advised Dexter to have his glasses fixed.
• Enfant Terrible: When Dexter turned him into a baby, Dad took a lot of enjoyment out of hurting his wife (also turned into a baby) with Dexter's machines.
• Eye Glasses: Like Dexter's glasses, they can change shape depending on expression.
• Flanderization: Became a Small Name, Big Ego in the later episodes.
• Genius Ditz: He's generally pretty care free and goofy, but he can be surprisingly crafty and manipulative when he wants to, bordering on The Chessmaster. If mom's muffins are involved, watch out!

• Heavy Sleeper: He combines this with sleepwalking. Sirens, explosions, electrocution, and strange chemicals do not deter his sleep at all. He also thinks he's a light sleeper.
• Jerk with a Heart of Gold: While he tends to pull petty pranks on his family, he does care for them.
• Jock Dad, Nerd Son: He's the Jock Dad to Dexter's Nerd Son. Or rather, he wants to be, but as several episodes have shown, he's really not much more physically capable than his son, he just likes sports more.
• Long Pants: His redesign for seasons 3 and 4 only, as he wore normal pants and shoes in the original run.
• Manchild: As seen above, he can be very childish and immature.
• Manipulative Bastard: He's this when he wants to be in "The Muffin King" and "Snowdown".
• Papa Wolf: He'll go through all sorts of danger if his kids are in trouble.
• Parental Obliviousness: It's amazing how he, along with Mom haven't figured out that the lab exists. This is partly explained by Dexter wiping their memories, but they only ever seem to find out when Dexter accidentally tells them himself.
• Sanity Slippage: In "The Muffin King", he gets so upset over his children preventing him from eating one of Mom's muffins too early that he ends up having a fantasy about ruling over a land inhabited by sentient muffins.
• Standard '50s Father: He walks a fine line between this and the Bumbling Dad.
• Trademark Favorite Food: He would do anything to get at least one of his wife's muffins.
• Took a Level in Badass: Dexter's dad goes from average middle class guy and sports enthusiast to daredevil stuntman in one episode of the later seasons.
• Took a Level in Dumbass: By the fourth season, he's become a complete nitwit. For instance, he doesn't know that he is being threatened legal action for stealing cable in "Bad Cable Manners" in spite of being repeatedly told so by the authorities that warn him and in "Tee Party" is shown to have no idea how golf works even though he was shown to be a fan of the sport in "Dad is Disturbed".
• Unnamed Parent: He's only ever referred to as "Dad".
• What the Hell Is That Accent?: His American accent is unknown; it could be his voice actor's accent of Texan, but he sounds Midwestern in some episodes, and it's not clear where he's from exactly, much like his son Dexter. In canon, it has never been confirmed where he is from, as compared to his wife.
• Would Hit a Girl: After being transformed into a baby, he had no qualms with injuring his wife with Dexter's inventions.

Mandark

Voiced by: Eddie Deezen

Dexter's rival and fellow scientist, who regularly tries to shut down his lab. He's in love with Dee Dee, but she never returns his affections. He was raised by two hippie parents. His real name is Susan.

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• Abhorrent Admirer: He's infatuated with Dee Dee, but it never works out for him no matter how hard he tries.
• Affably Evil: He usually uses his manners and has some Villain Respect for Dexter.
• Always Someone Better: He was this to Dexter before Villain Decay kicked in.
• Arch-Enemy: To Dexter. The two of them have a bitter rivalry.
• Ambiguously Jewish: He's never shown to be religious whatsoever but his last name does imply Russian-Jewish ancestry.
• Asian and Nerdy: He's half-Asian and a genius.
• Badass Bookworm: It should be expected as he's Dexter's Evil Counterpart.
• Badass Cape: Gets one in Ego Trip and the later seasons.
• Bad Boss: His young adult self in The Movie, who punishes one of his employees (Dexter) for almost being late by giving him a couple lashes with an energy whip in front of the other workers. One abuse too many leads Dexter to snap, beating Mandark's ass down and becoming his Future Badass self.
• Bald of Evil: His future self from the time of Dexter's Future Badass self has no hair on his head and has taken over the world by using the neurotomic protocore to make everyone else dumb.
• Big Bad: His appearances weren't as frequent in the first two seasons, but he is unquestionably the main villain in Ego Trip and the final two seasons.
• Brain in a Jar: His ultimate fate at the end of "Ego Trip".
• Breakout Villain: He appeared infrequently in Seasons 1 and 2, then pretty much became the 3rd main character after that.
• Brought to You by the Letter "S": There are two triangular cuts on the front of his hair, forming an "M".
• Can't Catch Up: Ego Trip reveals that his vast intellect has a cap to it which is why he starts to steal Dexter's ideas when they get older and the reason he uses the Neurotomic Protocore to steal the intelligence from the rest of the human race to enhance his own. All that "fat" his Bad Future self has? That's all grey matter.
• Character Catchphrase: “Deee-Deee.” Whenever he sees his crush, Dee-Dee, he slowly says her name in a lovestruck daze.
• Characterization Marches On:
  • A brief gag in his first appearance implied he could read minds, an ability that was never brought up again. Although he might have been making that up to intimidate Dexter.
  • Earlier on, he was merely Dexter's rival (and his lab had a more alien look). In later seasons, however, he was retooled as The Antichrist, with an Origins Episode that has him paint himself as a "monarch of darkness" (with his new lab being very demonic in appearance). Likewise, his parents are shown to be hippies, which you wouldn't expect with the surname "Astronomonov."
• Child Prodigy: A boy genius like Dexter.
• Cool Chair: In his first appearance, he had a hover-chair in his lab.
• Corrupt Corporate Executive: His youngest future self in Ego Trip, who eventually took control of the company he and Dexter worked for and started using its resources to advance his plans for world domination.
• Creative Sterility: Not shown in the majority of the series, but seems to be the case for the TV Movie Ego Trip. He's noted as having become dependent on stealing the ideas of Dexter in order to get himself to the top. This is taken to an even greater extreme when he becomes Overlord, as instead of creating anything superior, he brain drains the entire planet to ensure that no one else can be smarter than himself. Even his plan to fight the Dexters is basically to copy their idea of getting his other time-displaced selves.
• Cultural Rebel: One the reasons he decided to embrace science and evil was because he got fed up with his parents forcing their hippy lifestyle on him.
• Dark Is Evil: His lab in post-finale seasons. Also, of course, his nickname.
• "Darkness von Gothick" Name: His preferred, self-given alias.
• Depending on the Writer: He's either a villainous mastermind or just some kid Dexter's rivals with.
• Disproportionate Retribution: His hatred and obsession with ruining Dexter is later revealed to have stemmed from their first meeting, where Dexter laughed at his Embarrassing First Name. To punctuate this, Dexter doesn't even seem to recognise Mandark the second time they meet.
• Do Not Call Me "Paul": He changed his named from Susan to Mandark, because of Dexter laughing at said name, as well as his hatred for it. His parents still referred to his birth name later, making him angrily correct them.
  Mandark: My name is Mandark.
  Oceanbird: No, it's Susan.
• Dude Looks Like a Lady: Dexter first mistook Mandark for a girl due to his effeminate wardrobe and long hair as per the results of his parent's lifestyle. The fact his name was also "Susan" made the comparison to a lady all the more apparent.
• Embarrassing First Name: Retconned to Susan.
• Enemy Mine: Deconstructed. On a few occasions, Dexter and Mandark have teamed up against a common threat. However their hatred for each other tends to override their ability to cooperate and they usually just end up making things worse. They did pull it off successfully in "Mandarker" however, though still argued over their reward.
• Entitled Bastard: In his debut episode, he genuinely expects Dexter to help set him up on a date with Dee Dee, despite the fact that he had spent the entire episode one-upping Dexter and forced him to shut down his lab; Dexter only goes along with it because he realizes he can exploit Dee Dee's destructive tendencies to get back at Mandark and have his own lab shut down.
• Even Evil Has Standards: After a day posing as Dexter's mother, he is left so exasperated from spending a day in her shoes (and ceaselessly tending to every single trivial problem the other family members whine over), he aborts the plan to destroy Dexter's lab, yelling the family are nothing more than selfish creeps.
• Evil Counterpart: To Dexter; both are not geniuses, but Mandark is evil, tall, composed, and arrogant as opposed to Dexter who is good, short, loud, and insecure. His younger sister, Olga "Lalavava" Astronomov, is this to Dee Dee, a short and solemn Technician to Dee Dee's tall and joyful Performer; while Dee Dee unwittingly destroys Dexter's creations but truly loves her brother, Lalavava bullies Mandark mercilessly and displays little to no care for him. His parents also serve as not-so-evil counterparts to Dexter's, being a pair of 60's-era hippies in contrast to Dexter's straight laced 50's-inspired ones. His intentions towards science are also diametrically the opposite of Dexter's for while Dexter engages in science to improve mankind and the boundaries, Mandark wanted to use science as an extension of his own malevolent tendencies and take over the world.
• Evil Genius: His talents and competence are equal to Dexter's but it's implied in Ego Trip that he's not as imaginative as Dexter can be, which limits his genius.
• Evil Is Petty: He is obsessed with ruining Dexter and proving he is smarter than him. This reaches a point that in Ego Trip his future self not only uses his power to sadistically torture and break Dexter, but also uses the latter's protocore to drain everyone else's intellect, ensuring he is the sole unchallenged intellectual in the entire world. All of this because Dexter laughed at his Embarrassing First Name when they first met.
• Evil Laugh: "HA haha! HA haha haha!" The fact that he cries, coughs and chews in the same way makes it border on being a Verbal Tic.
• Expository Hairstyle Change: He was once long-haired, then got his iconic bowl cut when he decided to reinvent himself into Mandark, and those two bangs in the middle are the result of using a cracked bowl as his template, which fittingly form a meaningful "M" for Mandark similar to the way Matt Groening hid his initials in Homer Simpson's design as an easter egg.
• Eye Glasses: Much like Dexter, his glasses change shape to match his emotions.
• Fat Bastard: In the third future of Ego Trip, he is extremely obese and has to have a hook and later a robot carry him around. The official Cartoon Network Website nicknamed him "Fat Cat Mandark" back in the days it was still featuring digital collectibles that you could buy and trade these items from obtaining credits from playing games and being active on the website.
• Fate Worse than Death: At the end of Ego Trip and series as a whole, Mandark's final defeat is shown when his body to explodes, leaving behind only his brain and Dexter puts him in a jar and is forced to reside in the Dexter Museum for the rest of his life as punishment for his crimes.
• Faux Affably Evil: Since "Ego Trip", he has fallen into more of the fake-affable villain category.
• Flanderization: Became more and more like a stereotypical Evil Genius as time went on. He was just originally portrayed as Dexter's rival and at his most repugnant, just wanted his lab shut down. Suddenly it went from that to trying to take over the world. To a lesser extent, his crush on Dee-Dee.
• Four Eyes, Zero Soul: Mandark wears glasses and is Dexter's Arch-Enemy.
• Freudian Excuse: His parents were people perpetually stuck in the 60's summer of love (i.e. hippies) and constantly stifled his scientific curiosity. He tried his best to go along with it, but one chance meeting with Dexter on the day he moved into the neighborhood ended with Dexter laughing in his face. Needless to say that was the straw that broke the camel's back. Also Played With. He was shown to have always been born with a negative disposition and his parents really didn't understand him though when they did realized they were denying some of his needs, they left their home and traveled around, eventually settling in Dexter's neighborhood.
• Gender-Blender Name: His real name is Susan. He's very ashamed of it, too.
• Harmless Villain: He becomes this after going through Villain Decay.
• Hopeless Suitor: Is head-over-heels in love with Dee Dee, who is unaware... at best.
• Ink-Suit Actor: Bares more than a striking resemblance to his voice actor, Eddie Deezen.
• Ineffectual Sympathetic Villain: Deconstructed. Mandark constantly thrives to ruin Dexter, but the comical way his plans backfire and his general Sissy Villain image tends to make him quite pitiful. From the get-go however, the show pulls no punches in showing that Mandark's reasons for targetting Dexter are incredibly cruel and petty when he actually has the power to express it, with Ego Trip showing his increased evolution into a psychopathic Hate Sink. For extra points, he's still a Sissy Villain with Eddie Beezen's nasally voice acting throughout it all.
• Insufferable Genius: His ego is comparable to Dexter's.
• Jerkass: He makes Dexter's life miserable simply because he believes he's better than him.
• Knight of Cerebus: His villainy is taken much more seriously in "Ego Trip", since it is shown in the future that he has taken over the world and made everyone stupid just because he didn't want to share his knowledge with anyone else. Because of this, the future is shown to be a complete Crapsack World.
• Lean and Mean: He's a skinny Evil Genius, though his future self in Ego Trip is a Fat Bastard instead.
• Light Is Not Good: Mandark's lab before post-finale seasons. Compared to Dexter's, its interior was more of a bright white compared to Dexter's dark blue, and it even had some space-like structures around it (one of them even looked like the Death Star). There's also his usual getup - a white school shirt with a tie and blue shorts.
• Mad Scientist: An evil boy mad scientist with Evil Laugh and all.
• Meaningful Name: His vaguely Russian last name creates a parallel with Dexter's Eastern European Accent, and his first name drives him to reject the New Age hippie lifestyle in favor of hard science. His Russian sounding last name Astromonov also serves as a shout out to the series creator being a Jew from Russia. It's implied his father may be of Russian and perhaps Jewish descent to parallel Genndy Tartakovsky while his Asian mom parallels Yoko Ono.
  Mandark: And now I only needed a new name. A name to match the darkness that flows through me. A name that tells of the man I knew I could be. I was now…Mandark!
• Mirror Character: Both Dexter and Mandark are defined by their childish egos and temperament, to the point it's no surprise either would be completely insecure about the other's intellect and resent one another.
• Multiple-Choice Past: He has two different origin stories, but this is due to a Retcon.
• My Brain Is Big: He has a giant forehead to signify his intellect.
• Nerd Glasses: He wears thick framed Eye Glasses like Dexter.
• Nerdy Bully: A nerdy genius who often seeks to destroy both Dexter and his laboratory, and conquer the world. One of his future selves in "Ego Trip" still has the same nerdy appearance and is also an abusive boss who enjoys tormenting and torturing one of his employees (Dexter's future self).
• Not-So-Harmless Villain: Ego Trip eventually proves he can still be a threat, even after his Villain Decay.
• Ominous Opera Cape: Wears a long black cape in his alternate getup.
• Only Known by Their Nickname: His real name is Susan.
• Pet the Dog: When he's actually siding with Dexter or just taking a break from evil in general.
• The Power of Hate: While he was always intellectually gifted, he boosted his scientific endeavours dramatically just for the purpose of one-upping Dexter.
• Raised as the Opposite Gender: He was brought up as female, despite being biologically male, with Mandark's mom really wanting a girl but disappointed she didn't get one, so did it anyway.
• Real Men Wear Pink: Literally. His parents were expecting a girl, but when it turned out to be a boy, they decided to dress Mandark/Susan in pink clothing and flip-flops either way. Understandably, Mandark wanted to step out of this once Dexter ridiculed him for this and his name.
• Revenge Myopia: As of "Mandarker", he wants to outshine Dexter as revenge for Dexter destroying his lab through Dee Dee. While it does a good job creating sympathy for Mandark, what it fails to mention is that Dexter did that in retaliation for Mandark forcing him to shut down his lab. He curiously doesn't blame Dee Dee (who he has a crush on) even accusing Dexter of tricking her into doing it.
• Red and Black and Evil All Over: His alternate getup in the post-finale seasons is a leotard colored red and black which comes with a Badass Cape. There's also his lab, which has taken on a more spiky, demonic look.
• The Rival: Dexter's nemesis and rival boy-Genius.
• Shadow Archetype: Dexter by and large has an incredibly petty ego that will not take being anything below being the smartest most gifted person on the planet, however his talents and inventions are productive and he does have redeeming qualities. Mandark however, increasingly revolves all his intellect around his pettiness, most of his inventions and endeavours are designed around sabotaging or undermining Dexter, and his Who's Laughing Now? vendetta being the biggest drive for him even building a laboratory in the first place. Showcased vividly with both futures via either's use of the protocore in Ego Trip. While Dexter's is still a shameless Egopolis, the world is all the same utopian and thriving due to sharing his knowledge for benefitial purposes, while Mandark's is a total dystopia due to his spiteful reign and intentionally using the protocore to make everyone else stupider, caring only about being superior and getting the last laugh on those that undervalued him.
• Sissy Villain: In later episodes, his plans are more malicious, but his nerdish persona remains in tact.
• Smug Snake: He's often portrayed as condescending towards Dexter.
• Teacher's Pet: Competes for the role with Dexter.
• Team Rocket Wins: He gets a low-key victory over Dexter in "Framed", unintentionally stealing his popularity with a new fad.
• Took a Level in Jerkass: In the revival seasons, Mandark becomes significantly more evil, becoming Dexter's arch-nemesis rather than his rival.
• Vague Age: It is difficult to tell if Mandark is actually elder to Dexter, or if he is the same age as him but just appears older. On one hand, Mandark is in the same class as Dexter, and is generally treated as his equal. On the other hand, Mandark has a younger sister, and Dexter is implied to be a Grade Skipper. Further confusing matters is Mandark's infatuation with Dee Dee, who is older than Dexter and is hinted to be a sixth grader, which would put her age somewhere between ten and twelve.
• Villain Decay: When Mandark was introduced first, he was portrayed as being much smarter than Dexter, and his lab was (and still is) even bigger and more impressive than Dexter's. However, after Dee Dee destroyed his lab, Mandark fell to second place, and is no longer Dexter's equal. On the other side of the coin however, Mandark did become much more malvolent in later seasons, going from a mere Jerkass rival to outright antagonistic and, in Ego Trip's case, a genuine threat to the planet.
• Villainous Crossdresser: Once Mandark replaced Dexter's mom. No one in the family noticed it, until the real mom came by. Even then, they were completely stumped as to which was the real one.
• Villainous Crush: He has an unrequited crush on Dee Dee.
• Villain Respect: He hates Dexter but views him as a Worthy Opponent.

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