A driller was killed when the drawstring of an oversized jacket he was wearing caught in the rotating Kelly/crossover sub. Just prior to the incident the Kelly was drilled down. In preparation to making a connection the driller doped the joint of pipe in the mouse hole. After doping the joint of pipe, the driller was positioned next to the rotary table. This allowed the drawstring on his oversized, unsecured jacket to contact and became engaged in the rotating Kelly/crossover sub. The drawstring then pulled the jacket and the driller into the rotating Kelly/crossover sub resulting in a fatality.