Roundabout Kick

Power Attack (PH) , Improved Unarmed Strike (PH) , STR 15,

If you strike a successful critical hit with an unarmed attack, you can immediately make an additional unarmed attack against the same opponent, as if you hadn’t used your attack for the critical hit. You use the same attack bonus that you used for the critical hit. For example, Bujiko can make three unarmed attacks in a round, at base attack bonuses of +9, +6, and +3. If she gets a critical hit on her second attack, she can make an additional attack using her +6 base attack bonus. She then makes her third attack (at +3) as normal.

You can follow up on a particularly powerful unarmed attack with a mighty kick, spinning in a complete circle before landing the kick.