Every child fears under their bed. If they don't, they fear the closet, or maybe that little crack in the almost closed door.
Scientists know that children are more perceptive, they see things that adults don't. They aren't yet tethered into only accepting what society wants them to accept. They see what is truly there.
They see the monsters.
If you were to borrow a child's eyes and see through them for a night, you would go insane. To be able to see what you only dimly remember, burrowing into your covers whilst wearing those train pajamas, hoping to God that "it" doesn't see you back... would drive an adult crazy. Because adults forget the rules.
1) Cover yourself. If you can't see it, it can't see you. Even if it makes it harder to breathe.
2) Don't make any noise. Every whimper can lead to destruction.
3) Don't move. It attracts their attention.
4) Only light can make it go away. Bright light. Flashlights only make it worse.
Teens are caught in the middle. They can feel what's there, but they cannot see... And they forget the rules...
Why do you think there are so many insomniacs typing away at their computers, subconsioisly praying that the light from their computers will be enough to make it go away?
It's not.
Now look behind you with a child's eyes and try not to scream.