The April Fool is a prankster who plays very mean pranks on people.
The April Fool is the "embodiment of comedy". Although he is a minor character on the show, he played a big part in the episode "Fool's Day Out". His catchphrase is, "What's up with that?", similar to that of comedian Jerry Seinfeld, on who he is based. He also competed in the Fairy World games. The April Fool is typically seen telling jokes at Uncle Knuckle's Chuckle Bunker.
He wears a tacky yellow plaid jacket with a white shirt and a bow tie, and has black pants with a purple belt. He also wears a distinctive purple jester's hat with bells. He has buck teeth, but unlike Timmy Turner's teeth, his incisors seem to be the only teeth on his upper jaw.
Whenever someone begins to laugh when the April Fool is about to say his punchline, his body will inflate like a balloon. The April Fool says that when someone laughs when he is about to say the puchline, he will get comedy back up and will be blown right back to Fairy World. You can also bribe him with Spearmint Gum.
The April Fool first appeared in Christmas Every Day!, where he was a part of the Easter Bunny's scheme to capture Santa Claus, who was hogging the attention from all the other holidays because of Timmy Turner's everlasting Christmas wish.
In the episode Fool's Day Out, the April Fool is called upon by Timmy Turner whom had been the victim of constant pranks by his peers throughout the past few months. On April Fools' Day, Timmy was pranked yet again, and wished for the April Fool's help against Wanda's advice. The April Fool played several cruel jokes on Chester and A.J., and then nearly endangered Mr. and Mrs. Turner's lives, before Timmy put a stop to his prank. However, the April Fool was convinced that April 1st was his day for comedy, and wanted to deliver the ultimate punch line by using a rocket to push the Moon in the path of the sun's light, thus mooning the Earth and freezing it into a new ice age. Timmy was able to stop the April Fool from destroying the Earth by wishing for laughing gas to cover the world. The April Fool's weakness was his punchlines being interrupted by laughter before they were finished, and the non-stop laughter around the world caused him to get Comedy Backup. Timmy then launched the rocket at the over-inflated April Fool, blasting him away and back to Fairy World to face Jorgen Von Strangle's wrath.
His latest appearance was The Fairly Oddlympics from Season Six. He attempts to box with Head Pixie, however, the Head Pixie put gold into his boxing glove, which knocked the April Fool into a torch and the scoreboard. Needless to say, he lost the match.