Playdate of Doom is the twenty-second episode of Season 7.
Foop escapes from Abracatraz and, using a recording of Jorgen's voice, tricks Wanda into thinking that Jorgen has rehabilitated Foop and that the Anti-Fairy baby is ready for a play date with Poof. While Foop seems to have good intentions at first, as soon as Cosmo and Wanda turn their backs, Foop terrorizes Poof and then cries and blames Poof when his parents return. Only Timmy can warn Cosmo and Wanda of Foop's true intentions, but his pesky parents keep pulling Timmy away before he can speak, and if Poof keeps getting in trouble then he will then get thrown in another dimension.
At Abracatraz, Jorgen is getting ready to feed Foop by putting on extensive amounts of protective gear. Foop is considered the most dangerous and vile criminal at Abracatraz. Jorgen arrives at his cell and gives him beets and an ice cube, the latter which Jorgen believes Foop asked for no apparent reason. Before Jorgen leaves, Foop suspiciously asks him who he was again. When he leaves, Foop starts to execute his evil plan. Foop had been recording everything Jorgen had told him on his "Evil Baby's first tape recorder". Then he used a similar toy like laptop to create a tape and called Wanda. The poorly constructed fake call said Foop finished his rehab and can play with Poof, which Wanda believed. Foop laughs and says it was so easy, it was like taking candy from himself. Not long after, Foop escapes by using the square ice cube to create a crude dummy of himself, and then he escaped by tunneling through the ground.
At Timmy's house, Timmy was feeding Poof and Cosmo vegetables when Wanda appeared and told them that Foop was coming over for a play date. Cosmo and Poof spit out their vegetables onto Timmy. Wanda says that Jorgen told her Foop was rehabilitated. Timmy gave Poof another Good Baby star for finishing his vegetables, and placed it on a chart that was so full of stars they had ran out of space on the poster. Timmy doesn't trust Foop, even though Wanda tries to tell him that Jorgen is on top of things. At that same moment, Jorgen is taking a nap and accidentally releases all the prisoners in Abracatraz when his foot presses a red button. Timmy is skeptical and wishes for a disguise to spy on Foop. Cosmo dresses him up as a cleaning lady, although Timmy wanted to be a ninja but Cosmo evenly dubbs him "Timmy Sparklebottom".. Mrs. Turner comes into the room and thinks he is an ACTUAL maid. She tells him to take care of the hornets nest in the attic. Foop arrives through a magic door and calls Cosmo and Wanda "Auntie Wanda and Uncle Idiot". He gives them a suspiciously evil looking playpen which Wanda offers to have them play in, but Foop quickly panics and says he doesn't want to go in it because he had been in solitary confinement for so long.
Wanda makes the two babies hug. Poof doesn't want to, so Foop begins to cry obviously fake crocodile tears. Wanda takes away a Good Baby Star from Poof's chart, and Poof groans and hugs Foop. Foop whispers to Poof he'll destroy him. Timmy rushes back into the room and tells Foop he heard what he said with his hornet sting swollen ears. Before he can tell Cosmo and Wanda however, Timmy is chased out of the room and out the window by a swarm of hornets. Wanda poofs up the babies some play-do and table to play at, and disappears to feed Cosmo more beets which he does not like. Foop creates a purple play-do model of Poof and elaborates on what he meant earlier by tossing the model Poof into the playpen, causing it to be sucked into another part of the universe. The playpen is really a portal to oblivion. Timmy runs back in and tells Foop he knows what the playpen really is, but before he can tell Cosmo and Wanda, his father comes into the room and all the fairies poof away. Timmy's dad mistakes him for a ninja and pulls him away to make him make Dinkleberg "go away".
The fairies poof back into Timmy's room, and Poof tries to warn Wanda what Foop said but she doesn't believe him. When Wanda disappears again, Foop pours beats on his head and cries again. Wanda comes back and takes away another Good Baby Star from Poof. When she leaves again, Foop mocks Poof and tells him his idiot parents are going to send him to oblivion. Foop tells Poof "Let's play!" and this begins a montage of Foop crying, making blocks that say "Poof Stinks" and switching them to "Foop Stinks" when Wanda arrives, beating himself up and giving Poof a boxing glove, and throwing food at himself. Every time, Poof gets blamed by Wanda or Cosmo and loses a Good Baby Star until all his stars are gradually depleted. Foop even needed to start using eye drops he was crying so much. Cosmo also figures out he can use Foop's play pen to make beets disappear. When Poof has but one Good Baby Star left, Foop gives him a scary looking Jack in the Box. Poof turns the crank and it causes the entire room to explode. Wanda returns and thinks Poof is responsible for the destruction. She takes away his last Good Baby Star. Cosmo tells Poof that he has to take a time out in "the wonderful playpen that makes beets disappear".
Poof gasps and tries to run away, but Wanda grabs him and is about to put him in the playpen when Timmy barges in again and tells Wanda to stop because Foop is up to something. Foop takes out his bottle wand and zaps Cosmo and Wanda away. Foop grabs Poof and is about to throw him into the playpen portal, when Timmy throws his mop at Foop, knocking Poof away safely and causing Foop to fall into the portal to oblivion. While getting sucked into the portal, Foop vows revenge on Poof. Wanda apologizes to Poof and asks him to forgive her, and he hugs her. Timmy smiles and says "All in a day's work for Timmy Sparklebottom". Timmy also notes that they don't have to worry about Foop anymore. Meanwhile, Foop is floating through space in a mirror arguing with himself.