Answer:
What's a place you have left but didn't enter?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.
It can pierce the best armor and make swords crumble with a rub, yet for all its power It can't harm a wooden club.
A horrid monster hides from the day, with many legs and many eyes. With silver chains it catches prey. And eats it all before it dies. Yet in every cottage does it stay. And every castle beneath the sky.
Everyone has it and no one can lose it, what is it?
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.