Certifiable Super Sitter is the 35th episode of Season 10 and the season's third and final half hour special. It is also the final half hour special of the series. This episode marks the return of Poof and his only appearance in Season 10. This is also the first episode to premiere on Nicktoons instead of the main channel.
Chloe meets Poof for the first time when he comes home from school on Spring Break. Cosmo and Wanda win a free French Dinner, so Chloe gets to babysit Poof and his friends. Everything goes well until Vicky shows up.
Cosmo and Wanda are excited because their son, Poof is coming home on Spring Break. They decorate Timmy's bedroom in celebration of his return. When Timmy enters his room, Cosmo mistakes him for his son. He does the same thing with Chloe. Wanda then shows Cosmo a picture of Poof, and he thinks it's actually their son. Chloe then shows her excitement towards meeting Poof. Timmy says Poof is awesome, because he can wish up "totally inappropriate but super-cool stuff". He then shows Punchy the Boxing Kangaroo to Chloe. Cosmo then mistakes Punchy for Poof, and Punchy proceeds to punch him. Then, the Spellementary School bus arrives at Timmy's house, and everybody is excited to meet Poof. Cosmo mistakes a balloon for Poof, and he pops it. Poof gets out of the bus, and Timmy, Cosmo, and Wanda proceed to hug him. Wanda tells Timmy that Poof's voice is changing. Poof proceeds to do various impressions. Chloe then asks Poof if she can sniff his head, and Poof allows her to do so. Chloe describes the scent as smelling like "Bunnies and spring-time." Poof does a Donald Trump impression, and says he has brought some friends and a harbinger of doom with him. Then, Sammy Sweetsparkle and Foop proceed to enter the room. Foop wants revenge. Foop said he would have went home, but Anti-Cosmo and Anti-Wanda moved without leaving a forwarding address for him. Then he poofs up a league of fire and girls with dogs loose then Wanda takes it away and yells at him by grabbing his shirt, While outside Foop tricks Cosmo and Wanda in winning a french dinner. So Chloe gets to babysit Poof and his friends. Cosmo and Wanda get pushed in a black hole. Mrs. Turner asks Chloe to babysit Mr. Turner, while she goes grocery shopping. Chloe tells a joke which made everyone (except Foop) laugh. Chloe thinks Foop is good. Back inside Sammy Sweetsparkle is playing with toys. Foop destroyed it. Timmy asks Poof to poof up something. He poofs up a Mr. Croker punching bag and Punchy punches it really hard. Chloe sings a nursery rhyme, Foop puts up a spider but Poof got rid of it. Chloe hugs Foop. Foop didn't hate it. Suddenly Vicky arrives. She wants to destroy everyone, Chloe then walks up to her and Vicky spreads her super sitter book in half, She takes Poof's rattle and Foop's bottle. Vicky pushes Timmy and Chloe by using a mobile trap door causing them to fall down a basement. She makes Timmy run on the treadmill-floor and Chloe pick up garbage. Meanwhile, Vicky is baking biscuits and Sammy adds sprinkles on the biscuits and Vicky starts being mean again and Mr. Turner tries to escape but stopped. She then uses them as furniture so she can watch her favourite TV show. She finally uses Mr. Turner, Sammy, Poof and Foop run on a treadmill which powers a makeover machine. Meanwhile, Timmy and Chloe get a plan by picking up garbage so more of it will fall to fill up the room and then Chloe jumps off of the trap door and Chloe fights Vicky, luckily Foop saves Chloe by getting Vicky into saying "here Punchy" and Punchy punches Vicky really hard right into the wall Poof then gets his rattle and blasts Vicky away. Outside Mr. Turner, Sammy, Timmy, Chloe and Foop are in the pool tossing Poof like a beach ball. Chloe thanks Foop for saving her. Wanda and Cosmo and Wanda thanks Foop for the dinner recommendation. Wanda asks Poof if anything happened. Poof said that nothing happened. Mrs. Turner comes back. the episode ends with Punchy punching Cosmo.