Bone
What it does: It normally provides a framework for your muscles to sit on and protects your soft and squishy internal organs, but these ones just kinda lie around to remind you of death.
How to make it:
Drink plenty of milk.
What it makes:
The Bone combines with some Flame and Light Spirits to conjure the Ghost Girl. So now I guess we know whose bone it used to be. Yaaaaaaay.