The Terrible Twosome is the sixth episode of Season 9.
Poof is going through the Terrible Twos! Can Wanda and Cosmo calm him down?
When Timmy comes home, he sees that his room is a mess and asks Sparky if he messed it up. Sparky said he didn't, he been busy painting since he heard ladies love artists. Soon Poof showed looking angry and tried to attack Timmy and Sparky in Pacman styles. Cosmo and Wanda come much worn out and Wanda said that Poof is going through the terrible twos: A stage were every fairy babies rebel against everything and the only thing that calm Poof down is laughing at Cosmo hurting himself. Then, Poof goes crazy with the magic and luckily; Wanda wished up a shield. Unfortunately, magic doesn't work against the terrible twos, so Wanda poofed up Dr. Rip Studwell who was busy playing golf.
Unfortunately, he said that he can't do anything about the terrible twos but the good is, that the terrible twos aren't permanent and it only last for 12 hours, so Wanda tries to stop Poof by telling him to go to his room but it just make Poof leave the room. Timmy suggests that they should leave Poof alone so he can blow off some steam which he literally did.
Meanwhile in Anti-Fairy World, Foop realizes that Poof is going through the terrible twos and found Poof in the park. He tells Poof to join forces with him and become "POOP" and Poof then "says" that's a dumb name and Foop says that it didn't sound weird when he came up with it. Then Poof came up with the name "The Terrible Twosomes" and goes through training and their target is Crocker. They precede to tournament him with many ways. Crocker then says he has to get out of the park alive and bring his mom. Suddenly, Foop started acting nice much to his horror, and wonders why.
Soon Cosmo, Timmy, Wanda, and Sparky manage to get to the park and as soon as they get there, they noticed Foop is acting nice for no reason. They call Dr. Rip Studwell again and said that Foop goes through the TERRIFIC twos; the anti version of the terrible twos where anti fairy babies acts nice and doing nice things and Foop says he hates it while doing nice things. Poof then grows big and block out the sun turning the entire planet into another ice age. Wanda, Cosmo, Sparky, Timmy, and Foop take shelter in Timmy's house to survive the cold. Cosmo then tried to think how to stop Poof, but he got himself hurt. Then Timmy remembers that Poof laughs when Cosmo hurts himself.
Timmy and the others go up to get Poof to laugh at Cosmo, who tries improv rather than the physical pain, which only angers Poof. However, Cosmo is soon hit by a satellite and lemonade from the nice Foop. This hurts him but causes Poof to laugh, and Poof shrinks down and is back to his normal self again. In the end, Crocker gets spit out by the monster that ate him earlier and says he really has to bring his mother to the park and the episode ends.