Mandark (Dexter's Laboratory, seasons 1 and 2)

"'Dee Dee…'-His line whenever he sees Dee Dee, whom he has a crush on." '"Ivan "Mandark" Astronomonov" is the main antagonist of the Cartoon Network series, Dexter's Laboratory. He is Dexter's rival who often seeks to outsmart Dexter to prove once and for all that he is the superior genius. He is voiced by Eddie Deezen.

Why He Was A Good Antagonitic Science Rival

 * 1) He’s one of the most memorable Cartoon Network antagonists of all time.
 * 2) He has some memorable quotes, such as his iconic laugh "HA HA HA! HA HA HA HA HA!", "Dee Dee…", or "Yes Dexter, I can read your thoughts and I am smarter than you." from "Dexter's Rival".
 * 3) He is a good inventor and is perfectly capable to invent many things, like making a statue come to life, making robots and so much more.
 * 4) With that said, some of his inventions are quite creative, imaginative and somewhat impressive when you realize he is an 13 year old who does all of this rocket-science flawlessly and has these science-fantasy based inventions to rival Dexter's.
 * 5) His crush on Dee Dee is funny, and he often does anything to impress her or help her out, like when he saved her from his traps in the surfing contest in "Sun, Surf, and Science".
 * 6) His rivalry is with another inventor Dexter, because he was a scientist too, but a rather good one. He is the reason to root for Dexter instead.
 * 7) He is willing to put aside his rivalry against Dexter and team up with him to help save the day, in episodes like "Mandarker".
 * 8) He was charming and greatly villainous in Mh:greatestmovies:Dexter's Laboratory: Ego Trip, as he teams up with his future selves to take over the world and defeat the Dexters, and this is the only time it works in the story (as the revival seasons handled this poorly).
 * 9) He is greatly voiced by Eddie Deezen.

The Only Bad Quality

 * 1) He was badly flanderized in the revival seasons, becoming a bland, full-blown evil genius.