jumping frenchmen!

"Among the medical oddities mentioned in a December Wall Street Journal roundup was "Jumping Frenchmen of Maine Disorder," in which a person, when startled, would "jump, twitch, flail their limbs and obey commands given suddenly, even if it means hurting themselves or a loved one." It was first observed in 1878 among lumberjacks in Maine but has been reported also among factory workers in Malaysia and Siberia. It is believed to result from a genetic mutation that blocks the calming of the central nervous system (but could be merely psychological, from the stress of working in close quarters)."