When i went back in time to my childhood some things that cheeped me out was
a jack in a box my sisters dolls so i went on Google and got some images and i tried to make them in maya.
Puppet this is creepy and a good start i think
This is my maya.
My next one is a bike
I think in a house or a empty street this will be more effective. This is just the render
A man in a room.
This is just a thort but i think its a good start for some thing creepy a bit more work and it might be a contender
And my last one is a jack in a box this is bast with a doll head. I made the head in zbrush