Used to threaten, used to defeat. Sometimes it grows, sometimes it shrinks. Used to conquer, used to protect. It marks your downfall, it marks your success. The true god of war, the creator of mess. What is it?
This was Gollum's final riddle from The Hobbit:
"This thing all things devours;
Bird, beasts, trees, flowers;
Gnaws iron, bites steel;
Grinds hard stones to meal;
Slay king, ruins town,
and beats a mountain down."
A harvest sown and reaped on the same day In an unplowed field, Which increases without growing, Remains whole though it is eaten Within and without, Is useless and yet The staple of nations. What is it?