Frostbite. Both of my feet went dead during the Packers vs 49ers playoff game at Lambeau last season. They thawed on the car ride back home. It was sort of like if you took the "pins and needles" sensation and replaced the pins with screwdrivers and the needles with drill bits and also lit them all on fire. I tore a flannel sweater apart with my teeth to try and cope with the pain. It didn't help.