Original air date: 5/17/2003 (produced in 2002)
Episode number: 30a
Timmy invites Chester and AJ to his treehouse for a sleepover, but when the two get into a fight over whose costume is better, they leave and hold their own sleepovers, which they both want Timmy to attend or they won't be his friend anymore. So Timmy poofs himself back and forth between the two sleepovers, but when both sleepovers end up being lame (as Chester only has a radio and AJ's parents set up parental blocks), Timmy devises a plan to get his friends to stop feuding. Meanwhile, Cosmo starts to befriend random animals he sees, but they are all killed quickly.
This episode contains examples of:
- Feud Episode: Between Chester and AJ.
- Shout-Out: The animals Cosmo meets are all named after Jimmy Neutron characters (Carl for the ant, Cindy for the bee, Jimmy for the cat).
- Slumber Party: What was thrown for the episode.
- Two-Timer Date: AJ and Chester say if Timmy doesn't attend their own sleepover they won't be his friend anymore. He uses Cosmo and Wanda to teleport back and forth between both sleepovers without either noticing, but it quickly becomes apparent that both of their sleepovers stink and the best solution is to get them to be friends again.
- Visual Pun: The parental block literally shows a rotating block to the repeated stanza, "Block, block, block, block, block...".
