Answer:
I am what no man ever yet did see, which never was, but always is to be. What am I?
The more you take of me the more you leave behind.
What goes through a door but never goes in and never comes out?
I am the beginning of the end and the end of time and space. I am essential to creation and I surround every place.
I stand in one place yet I fill a whole room. I can be filled with molten rock and come in every hue.
Often cooked as fillet, this meat comes from an animal that swims underwater.