You're the one under the bed.

The four walls start moving
They're closing in
Raping the air you breathe
Terrorise your fear
Can you feel the pain coming in through the window pane?
No escape tonight
It's a regular night you're on
Ordinary pain
The pills you take
Leave your sanity at stake
But the bruises left when you scream
Prove that you're intactly awake from your dream