Ghosts, easy Halloween

i saw these at Micheal's for $4 and figured I could make them at home for free, and Halloween decor should be free or close to it.  Almost too easy to publish, but a nice simple project to liven up the holidays.  Easy for kids. 

Step 1 What you need

White sheet.
Cardboard, preferably thick, double corrugated.
A hollow ball of some kind.  Tennis ball racket ball,
Thread, wire, rope.
Knife, eXacto knife,
Markers