The Forget-Me-Knob is a magical "memory wiping" door knob that only appeared in Abra-Catastrophe!
The Forget-Me-Knob is a golden doorknob that causes whoever makes contact with it to forget whatever they were doing. It's memory wiping capabilities are limited to wiping the reason the person in question was going into Timmy's room
Later on, the Forget-Me-Knob saved Timmy from losing his fairies when Jorgen Von Strangle showed up to take them away, as he had revealed his godparents to his parents. Timmy, who had just removed the knob from his door, threw it at Jorgen's head, causing him to forget why he was visiting Timmy. In his confusion, Cosmo and Wanda convinced him that he was there to reassign them to Timmy, which Jorgen did so and left.
- When Timmy enters his room after Mr. Crocker begins to transform the world into his domain, the Forget Me Knob is apparently gone and Timmy and Cosmo were able to get into the room with no ill effect (although Cosmo may have simply pushed the door down).