A riddle from C.S. Lewis’ The Hobbit... 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. [Answer: Time] 'Ooh!' said Susan, 'I'd thought he was a man. Is he—quite safe? I shall feel rather nervous about meeting a lion.'