Stone Bones
From HGWiki
Caster Level: Accursed Pariah 2; Cleric 2; Sorcerer/Wizard 2
Innate Level: 2
School: Transmutation
Descriptor(s): Magical armor
Component(s): Verbal, Somatic
Range: Touch
Save: Harmless
Spell Resistance: No
Area of Effect/Target: One undead creature
Duration: 10 Minutes / level
Description: You cause the target undead to gain a +3 natural armor class bonus, due to the thickening of its bones.
Notes
When cast by an Accursed Pariah upon himself, the Stone Bones spell grants 1% physical immunity for every 2 caster levels. In addition, all critical hits will do half damage, as if the caster had 127 Parry skill.