Answer:
I'm white, I'm round, but not always around. Sometimes you see me, sometimes you don't.
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.
I weaken all men for hours each day. I show you strange visions while you are away. I take you by night, by day take you back. None suffer to have me, but do from my lack.
What comes once in a minute, twice in a moment, but never in a thousand years?
What zips through the sky with a tail of fire and dust. It could be an omen, its origin to discuss?
I have two eyes in the front and a lot of eyes on my tail
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?