Answer:
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
I am a box that holds keys without locks, yet they can unlock your soul.
They made me a mouth, but didn't give me breath. Water gives me life, but the sun brings me death.
Lighter than what I am made of, More of me is hidden Than is seen.
When I get closer my tail grows longer, but when I go away my tail leads the way.
I can only be played on a windy day
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?