Answer:
Never resting, never still. Moving silently from hill to hill. It does not walk, run or trot. All is cool where it is not. What is it?
I have green hair a round red head and a long thin white beard.
Though desert men once called me God today men call me mad. For I wag my tail when I am angry. And growl when I am glad.
Face with a tree skin like the sea. A great beast I am. Yet vermin frightens me.
What is harder to catch the faster you run?
I flow from the Homerβs mouth when he sees doughnuts.