The secrets of the magic were jealously guarded by the goblins, and no one had undergone the procedure in over five hundred years. Harry’s body had been changed, made stronger, faster, more resistant to pain and injury. He had grown several inches in the space of a few hours, broader around the shoulders and chest, thicker arms and legs of sinewy muscle and even got a squarer jaw. All of these "mutations’ had made Harry into one big, angry killing machine that could withstand pain more than any human should have been capable of bearing.