Answer:
What weaves webs as they grow?
Forward Iβm heavy, but backwards Iβm not.
There is a creature of God whose body is hardΝΎ it does not wish to eat unless you strike its head.
What's black when you get it, red when you use it, and white when you're all through with it?
Used left or right, I get to travel over cobblestone or gravel. Used up, I vie for sweet success, used down, I cause men great duress.
You use it between your head and your toes, the more it works the thinner it grows.