Forgeticen, Forget-a-cin, or Forgeticin, is a memory wiper device used by Fairies to erase the minds of humans that have discovered them, and of godchildren who have lost their fairy godparents by breaking several rules, making a secert wish, or not wanting them any more.
It is used by Jorgen Von Strangle to erase a godchild's memories of their godparents once they become too old for fairies, or if the godchild's fairies are discovered by humans. Any humans that saw the fairy also have their minds erased. It first appeared in "The Secret Origin of Denzel Crocker!" but it is mentioned by name in "Fairy Idol". When Jorgen gave the ten year old Denzel Crocker an overdose of it, it caused him to be horribly disfigured, leading him to the condition he is in.
Disclaimer from Fairy Idol
Forgeticin side effects might include nausea, blurred vision, drowsiness, and stomach cramps. Your doctor may have to perform a painful blood test to see if Forgeticin is right for you. Forgeticin should not be used in the presence of cats, banjos, and Democratic presidents. Forgeticin, don't forget it. Forget what? Why am I here? Who are you people?
It is a reference to the Neuralyzers from the film Men In Black.
As demonstrated by the aforementioned episode, "The Secret Origin of Denzel Crocker!", it has the potential to cause permanent physical damage if the device is used too much on a resisting godchild, such as Mr. Crocker.
The disclaimer for Forgeticin is the second time real-life politics are mentioned in the series (Democratic presidents). The first time is in "The Secret Origin of Denzel Crocker!" when Timmy travels back to 1992 and one of the cars has a sticker for Clinton/Gore.