Vital Strike (Combat)
Using a standard or full round action, 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 weapon’s damage dice for the attack twice and add the results together before adding bonuses from Strength, weapon abilities (such as flaming), precision based damage, and other damage bonuses. These extra weapon damage dice are not multiplied on a critical hit, but are added to the total.
Note: Vital Strike may not be used with an Attack of Opportunity, Charge, Cleave, Great Cleave, or Spring Attack.
Link: Pathfinder Forum