Answer:
Rotten trees and Jack-O-Lanterns have this characteristic in common.
Once you know it exists, it no longer exists. What is it?
Who plays when he works and works when he plays?
It's shorter than the rest, but when you're happy, you raise it up like it's the best. What is it?
What is often returned, but never borrowed?
What did the piece of wood say when he saw the screwdriver and screws approaching?
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?