Here is a fun trick me and my brother made up:
The way it works: When someone is using the pencil and tries to erase with it the eraser will draw, scribbling on their page, It works really well!
You'll need two pencils
First, break the lead out of one of the pencils. Then, shove the lead piece into the eraser of the other pencil so its barely showing.
After that give the pencil to somebody and wait til they have to erase something and see how frustrated they get.
Ask if you have any questions