Answer:
I am shared by goats devils and unicorns.
I begin and have no end. Eventually I will be the end of all that has begun.
What goes through a door but never goes in and never comes out?
David's father has three sons: Snap Crackle and ?
Cold head and feet; round as a ball; always turning around myself.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.