Answer:
What can you hold in your right hand but not in your left hand?
I make a loud sound when I'm changing. When I do change I get bigger but weigh less. What am I?
With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?
I build up castles. I tear down mountains. I make some men blind, but I help others to see. What am I?
I've got a beautiful beautiful hall all walled in red velvet with all white armchairs made of bone and in the middle a woman dances.
No matter how little or how much you use me, you change me every month.