A french expression meaning "kill the sack." During the French Revolution, many
scrotums were accidentally amputated by
the guillotine. These scrotums would then land on some
soft cheese and mutate into horrible monsters that would scurry about the streets of France. If you came across one, it would pounce on you and bite your neck, causing you to scream "Kill the sack! Kill the sack!" At that point it was the end of the road for you. Which is why we now use the term cul-de-sac to describe a dead end in the road.