Answer:
What can bring back the dead. Make us cry, make us laugh, make us young. Born in an instant yet lasts a life time?
Steals an event or even a mood. Reveals the truth or shatters it.
Useful tool for who in darkness dwell. Within you, corrupting like a deadly spell.
It's usually found dried, but often kept slicker. Above another need, it's said to be thicker. What is it?
Round like a dishpan and smaller than a bathtub. But the ocean can't fill it. What is it?
You use it between your head and your toes, the more it works the thinner it grows.