Stone Colossus
( Races of Faerun, p. 169)[General]
You can focus a part of your power to increase the toughness of your skin.
Prerequisite
Base Fortitude save +3, earth genasi,
Benefit
When you use the attack action or full attack action in melee, you can take a penalty of as much as -5 on your attack and add the same number (up to +5) to your Armor Class as a natural armor bonus. This number may not exceed your base attack bonus. The changes to attack rolls and Armor Class last until your next action.