Answer:
I shrink smaller every time I take a bath. What am I?
What loses its head in the morning but gets it back at night?
People buy me to eat but never eat me. What am I?
Crooked as a rainbow and slick as a plate ten thousand horses can't pull me straight.
With a halo of water and a tongue of wood; stone as skin long I stood.
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.