Answer:
What goes in the water red, and comes out black?
Crooked as a rainbow, and slick as a plate, Ten thousand horses can't pull it straight.
My second is performed by my first, and it is thought a thief by the marks of my whole might be caught.
Not born, but from a Mother's body drawn. I hang until half of me is gone. I sleep in a cave until I grow old. Then valued for my hardened gold.
A time when they're green. A time when they're brown. But both of these times, cause me to frown. But just in between, for a very short while. They're perfect and yellow. And cause me to smile.
What is full of holes but still holds water