During the 1998 Royal Rumble, Shawn Michaels suffered a serious back injury in a Casket Match against The Undertaker. What first seemed like a minor incident turned out to be far more severe. Michaels had herniated two discs and crushed another. The injury forced him to miss several prime years of in-ring action, sidelining him for much of the Attitude Era and reshaping his career | Ruthless Attitude