The Barkskin spell provides the recipient with skin as tough as bark.
|“|| Barkskin |
When a priest casts the Barkskin spell upon a creature, its skin becomes as tough as bark, increasing its base Armor Class to 6, plus 1 for every 4 levels of the priest: Armor Class 5 at 4th level, Armor Class 4 at 8th, and so on. In addition, Saving Throws vs. all attack forms except magic gain a +1 bonus. This spell can be placed on the caster or on any other creature he touches.