What was Shelob, and more importantly, what was Ungoliant?

[obloquy]

Originally Posted by Gwathagor

As I see it, Ungoliant and Bombadil were created incidentally, as manifestations of natural forces.

And why do you see it that way? If it's just because you like the idea, fine. If not, could you please elaborate? Is there any evidence for the theory? Anything that might preclude the possibility that these two are creatures of a more substantiated nature?