Irresistible Mountain Strike p. 83
You slam your weapon into your foe with irresistible force. He can barely move as he struggles to marshal his defenses against you.
Your mighty attack causes your opponent to stagger aimlessly for a few key moments, leaving him unable to act fully on his next turn. If the target of the maneuver fails the save, they lose their standard action for that round. They may still take full round actions, such as the full attack action, casting a spell, or using the withdraw action, but other actions that require a standard action (such as initiating some maneuvers or casting certain spells) cannot be taken.
As part of this maneuver, you make a single melee attack. This attack deals an extra 4d6 points of damage. A creature hit by this strike must also make a successful Fortitude save (DC 16 + your Str modifier) or be unable to take a standard action for 1 round. It can otherwise act as normal. A creature that successfully saves still takes the extra damage.
This maneuver functions only against opponents standing on the ground. A flying creature or a levitating target need not save against the action loss effect, but still takes the extra damage.