Answer:
What I am filled, I can point the way. When I am empty. Nothing moves me. I have two skins. One without and one within.
The weapon of choice to create the biggest shock.
I'm not man's best friend, I'm their enemy, I can mark your end, yet you do not see me, I am very small, but very tough, If you have me, then you have it rough.
You can see nothing else, When you look in my face, I will look you in the eye, And I will never lie.
The moon is my father. The sea is my mother. I have a million brothers. I die when I reach land.
If lightning strikes an orchestra who is the one most likely to get hit?