The material below is Open Game Content from a 3PP Source
Vital Strike (Combat)
You make a single attack that deals significantly more damage than normal.
Prerequisites: Base attack bonus +6.
Benefit: When you use the attack action, you can make one attack at your highest base attack bonus that deals additional damage. Roll the damage dice for the attack twice and add the results together, but do not multiply damage bonuses from Strength, weapon abilities (such as flaming), or precision-based damage (such as sneak attack). This bonus damage is not multiplied on a critical hit (although other damage bonuses are multiplied normally).