Answer:
Light hides me and darkness kills me. What am I?
I am shared by goats devils and unicorns.
I have no life but I can die. What am I?
I fly when I'm born. I lie when I'm alive. I run when I'm dead. What am I?
Die without me, never thank me. Walk right through me, never feel me. Always watching, never speaking. Always lurking, never seen. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?