Answer:
Longer than a decade and shorter than a milennium
Once you know it exists, it no longer exists. What is it?
Lovely and round, I shine with pale light, Grown in the darkness, a lady’s delight.
Spies and detectives do this to phones and musical shoes make this sound.
The celebrities of high school were part of this crowd.
Break me and I am better immediately set and harder to be broken again.
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?