Damage Reduction (Su)
The creature ignores damage from most weapons and natural attacks. Wounds heal immediately, or the weapon bounces off harmlessly (in either case, the opponent knows the attack was ineffective). The creature takes normal damage from energy attacks (even nonmagical ones), spells, spell-like abilities, and supernatural abilities. A magic weapon or a creature with its own damage reduction can sometimes damage the creature normally, as noted below.
Any weapon more powerful than the type listed in the note also negates the ability. A weapon with an enhancement bonus due to magic is considered more powerful than any weapon that does not have such a bonus.
For purposes of harming other creatures with damage reduction, a creature’s natural weapons count as the type that ignores its own innate damage reduction. However, damage reduction from spells does not confer this ability. The amount of damage reduction is irrelevant.