you can kill a bearing by skidding the balls......rapidly spiking the engine RPM before everything is fully warmed up can cause the balls to skid on the race and start tearing up the bearing surface..... Usually if this happens you will see pitting and scarring on the race like in the picture Monty posted.........

Also to add..I have seen similar damage from the bearings not being properly broken in properly.... new bearing, cold engine, rapid RPM spike..snap !