Stone bones

Stone bones was a spell used by clerics, sorcerers, and wizards.

Effects
When cast, the spell transformed the bones of an undead creature to become stronger and thicker. As a result, their bones were as strong as stone. The spell also worked on undead creatures that had an exoskeleton.

Components
In addition to verbal and somatic components, the spell required an arcane focus, a small granite skull.

History
It was rumored another version of this spell existed, with the same effects but used on living creatures. It likely caused tremendous pain to the targeted creature and it was probable that the clerics of Loviatar used this spell.