This spell causes a massive stone boulder to crash down into the spell’s area, making an attack roll of 1d20 + your caster level + your Wisdom or Intelligence bonus against any creatures in that area. Targets struck are dealt 5d10 bludgeoning damage. The stone boulder then explodes, doing damage to everything within a 20-foot radius (including creatures hit by the initial attack) with the shrapnel. Creatures must make a Reflex save or suffer 5d4 slashing damage. All damage dealt by this spell acts as a magic weapon for purposes of penetrating DR.