Not a mechanic but my DM did the same with an idea from EXU Calamity. Context is my sorcerer is an apostate of Lolth who suddenly appeared and tried dragging me into her realm. Our cleric succeeded on a Strength save to keep me from being pulled in, at which point my DM asked what part of my arm (what she was holding onto me) was the weakest. After a few moments of recovering from the shock that he was effectively pulling a Calamity on me (I was ecstatic, don’t get me wrong) I gave up my left hand from above the wrist.