Spellementary School is the thirty-eighth episode of Season 7.
With Poof's first day in Spellementary School, he and Foop compete to be the most popular student there, but Foop takes it to extremes when it becomes clear that his classmates favor his fairy counterpart more than him.
Cosmo and Wanda wake up Timmy early and tells him that it's the first day of school, and Timmy wonders what she is talking about as it is the middle of July. She tells him it is actually Poof's first day while she tries to dress him in a formal school uniform, which Poof switches in defiance several times until he finally obeys her. Wanda says that every fairy needs to go to Magic School. They poof into Cosmo and Wanda's Magic Van. Cosmo says he never went to Spellementary School and proceeds to drive the magic van to the school, but crashes and says he never went to Driving School either. At Spellementary School, Wanda is very sad to leave Poof alone, so Timmy says that she and Cosmo still have him. So Wanda poofs Timmy into a diaper and bonnet. Cosmo gives him a baby bottle and puts it in his ear, revealing he never went to Parenting School either. In the playground we see several of Poof's classmates, two leprechauns, four elves, two lawn gnomes, and lots of tiny sprites. One stands on Cosmo's nose and he tries to swat it by hitting himself with a shovel.
Foop arrives and declares that Spellementary School will be his future conquest, he will become the most popular kid in school. Mrs. Powers is their school teacher and introduces herself, and then says they have a celebrity in the class amongst them: "Foop!...spelled backwards!!", and Poof cheered by the class much to Foop's annoyance. Foop also begins to show a split personality when he argues with himself, with the other half of his personality being much nicer but wimpier. Poof quickly wins the hearts of the other classmates, even as Foop tries to show him up at lunch room jokes, basketball, and basic math, failing each and every time. Soon it is time to elect a class President and the two candidates, Poof and Foop, prepare to give speeches. Foop gives a speech about "Fiery death!" and is booed by his classmates, while Poof simply says his name twice and is revered much to his Anti-Fairy counterpart's bewilderment. Poof is elected even though Foop rigged the ballots with hundreds of votes in his name, Foop's other nicer split personality reveals he changed all the votes to Poof's name.
Poof's latest victory finally sends Foop over the edge, and he decides to turn the school into an evil one where he is the most popular. Chains appear from the walls and tie up Mrs. Powers and her students, while Poof dresses as Obi-Wan Kenobi (from Star Wars) and activates his rattle wand into a lightsaber. Foop dresses as Darth Maul and turns his bottle wand into a double-bladed lightsaber. The two start battling, and midway through the fight Foop tries to lure Poof to becomes his vice-president in his new school, but Poof denies his offer and as the students refuse to say they like him over Poof, he decides to throw the whole school into a black hole. Foop poofs outside of the school and watches as it is being sucked into a black hole, laughing maniacally as best as he could, when suddenly a school bell rings and when he opens his eyes he is standing at the front of the regular classroom, It was only Foop's dream. Foop asks what is going on, and Mrs. Powers says that at the end of the school day, everything turns back to what it was before school started, and that is what "saved by the bell" means in Spellementary School. When Cosmo, Wanda, and Timmy (still dressed like a baby, happily sucking on a pacifier) come to pick up Poof, who is heading out the front door with Foop. Cosmo tells Foop has a sprite on his nose, and hits him with a shovel repeatedly as he tries to swat it away and this continues to no end as the episode ends there.