Rumpus Riddle Answer #4

Okay, I admit that I have a thing for The Hobbit and LOVE the chapter "Riddles in the Dark." This is the second riddle from J.R.R. Tolkien's masterpiece (yes...it is a masterpiece, being the groundwork for The Lord of the Rings -- which is indeed a magnificint, masterful, work of literature.)
The Riddle:

"This thing all things devours:
Birds, beast, trees, flowers;
Gnaws iron, bites steel;
Grinds hard stones to meal;
Slays king, ruins town,
And beats high mountain down."

The Answer? I would first like to thank those of you that guessed that 'water' was the answer. Water is a very good guess, but....incorrect, I'm afraid.

The correct answer is.....Time!

P.s. Thanks also to Bilbo Baggins who guessed 'Halliburton' -- though woefully lacking in substance, we'll give him style points for that one.