Fairy Idol:

Norm the Genie returns and tricks Cosmo and Wanda into disliking Timmy by replacing him with a selfish, unappreciative clone. When Cosmo and Wanda quit, a singing contest is held in Fairy World to determine who gets to replace Timmy's godparents. Timmy, on the other hand, has his memories wiped, but unbeknown to Jorgen, he only succeeded in wiping the Timmy clone's memory. Using a portal to Fairy World that Mr. Crocker had recently constructed, he journeys to a world where he is no longer welcome in an attempt to win back his fairy godparents' trust.