Answer:
They are many and one, they wave and they drum, used to cover a stare, they go with you everywhere.
I am ten little beans your look at everyday.
The more of me there is the less you see.
What happens when you throw a green stone into the Red Sea?
Face with a tree skin like the sea. A great beast I am. Yet vermin frightens me.
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.