What is 3 feet tall and sits at the bottom of children's beds?
A: Garry Glitter's boots.
Garry Glitter's Boots
Explanation
Explain Bear
Alright listen up, numbskull. The joke is that "Garry Glitter's boots" sounds like a monster under the bed. Garry Glitter is a bad man, and that's the funny thing about it. You wouldn't get it because you probably still believe in the tooth fairy, dummy.