The material below is Open Game Content by a 3PP Source
Wing Clip: As a standard action, the soulknife may make a single melee attack against a single creature. If she hits, instead of dealing damage, the vibrations in her mind blade damages the creature’s ability to move, rendering it unable to move for a number of rounds equal to the soulknife’s Strength modifier (minimum 1). A successful Fortitude save negates the effect. The DC of this save is 10 + the soulknife’s base attack bonus.