The control you exercise over your beast within allows you control over others with the ability to change their shape.
Prerequisites: Shifter, Improved Unarmed Strike, Stunning Fist.
Benefit: You may expend a daily use of your stunning fist to disrupt a shapechanger and cause it to instantaneously revert to its natural form. This attack works identically to Stunning Fist, except if the opponent fails its save, it reverts to its natural form (thus ending a shifter’s shifting) instead of benig stunned.
Special: A fighter may select Disrupting Strike as a fighter bonus feat.
Source: Dragon Magazine #355 (Page 76)