You can get creative with this as well, use any type of fabric, add in some stitches and staples, etc.
The supplies you will need are as follows:
A paintbrush or sponge brush
a cheap mask, one with a smoothish surface works best
duct tape (Only if you are borrowing a mask and want to keep it after you make your mold on it.)
Elastic or string of some sort
Some awesome tunes to listen to whilst you work
Paint and/or eyeshadow to paint the mask with, add some fake blood too if you want!
Fabric of any kind