Planar Aegis

You draw motes of essence from material native to a plane that has elemental or energy essence traits, weaving the essence together into a shield of force. Choose an essence trait from the list below; the material component for this spell must come from a plane that has the essence trait you chose. Each essence trait has an associated damage type (see the table below). Any creature that hits you with a non-reach melee weapon, natural weapon, or unarmed attack takes 3d6 points of damage plus 1 point per caster level you have (maximum +20) of a type corresponding to the essence trait you chose. In addition, you take only half damage from attacks or effects of the associated damage type, and if such an attack or effect allows a saving throw for half damage, you take no damage on a successful saving throw.