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 mountain down.
(In reply to
Nice Puzzle by K Sengupta)
In THE HOBBIT, Bilbo Baggins and Gollum test their wits. If Bilbo wins, then Gollum has to show him the way out of a tunnel. However, Gollum will devour Bilbo if he loses.
This enigma is the final Riddle #5 of the five riddles that Gollum posed to Bilbo.