Answer:
I have a little pool with two layers of wall around it. One white and soft and the other dark and hard. What am I?
I spend most of my day eating white. When I am quick enough I get rewarded with fruit and something blue. In a dark room with blue walls I run from the ghosts that roam the halls
An open ended barrel I am shaped like a hive. I am filled with the flesh and the flesh is alive.
I am the ultimate killing machine used not once but TWICE I can be made by humans.
I can't go left, I can't go right. I am forever stuck in a building over three stories high. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.