Answer:
The sharp slim blade, that cuts the wind. What is it?
This thing all things devours: Birds, beasts, trees, flowers; Gnaws iron, bites steel; Grinds hard stones to meal; Slays king, ruins town, And beats high mountains down.
A house full, a yard full, a chimney full, no one can get a spoonful.
The person who makes it has no need for it. The person who purchases it does not use it. The person who does use it does not know he or she is. What is it?
Of these things - I have two. One for me - and one for you. And when you ask about the price, I simply smile and nod twice.
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.