Object that changes the structure of the back bones to form symbols drawn on it. Causes much pain while transforming. Weakens bones making them easier to break. Can make the bones take forms which makes them immobile. Can make bones grow out of the body to form for example horns. Was found together with old sheets of paper with instructions on them and also its use. Was used to form pentagrams on backs of sacrifices for some cultists.
I've decided that it is a kind of bowl or cup. Any liquid poured in it will turn into a paint which you put on someones back to change the bones.