You ever hang out in a field and think to yourself, "baby dinosaurs must have been huge!" If you do, then you know that dragonflys are like dragons in our dreams.
Remember when Harry, with all of his belongings, ran into the wall labeled 9 3/4? It was magical. When I did it, I got a concussion; six to one, half dozen to another.
Why monster bookmarks? Because there is a monster in all of us, and it is cool to show your weird.