Answer:
I am lighter than the material I am made of. You see parts of me but more of me is hidden underneath.
You may enter, but you may not come in. I have space, but no room, I have keys, but open no lock. What am I?
Draw fire or fill me; I'm still empty.
I am shared by goats devils and unicorns.
What word has kst in the middle, in the beginning, and at the end?
I tell people to be careful when handling boxes.