The Fairly OddParents (2001) : 6x10

Dark Laser's back and after trying (and failing) to destroy Timmy, he adopts the saying, "if you can't beat 'em, get 'em to join you." He offers Timmy a scholarship to "Dark-Mouth University" in an effort to get him to become his evil apprentice. Timmy refuses but Mom and Dad – excited that someone else is going to pay for Timmy's college – eagerly accept the offer. Timmy is given a dark suit with dark powers and the proviso that if Timmy tries it and doesn't want it, Dark Laser will leave Earth alone forever. Timmy agrees, and soon it seems he's fallen under the evil spell of the evil suit.