Answer:
Deposit red liquid in me.
Light hides me and darkness kills me. What am I?
I am a portal to another world which you cannot enter. Only you can see me but I can't see you.
What can be as big as an elephant but weighs nothing?
I am gentle enough to soothe your skin, light enough to fly in the sky, strong enough to crack rocks. What am I?
What language does a billboard speak?