One finger death punch

Must have the martial arts feat

Upon hitting with an unarmed strike the monk can spend 3 ki points to perform a one finger death punch. Attacker makes a martial arts (Dex) check DC 18.  The victim makes a dexterity save of DC 15 to take half damage. If fails take 10d8 of blunt damage. If this kills the victim the monk gets one Ki point back. If it does not the victim is knocked prone.