What do Jim Carrey, Cher, and the phantom of the opera all have in common?

I hide the world, then let it through, With just a pull, I change the view. On stage or window, I may fall, what am I, soft divider for all?

Fast and high, I’m a swift little fellow Painful to do when your throat is not mellow

I'm used to build a dragon's hide, Or to give an idea of size, Lady Justice holds me high, I'm the ascension notes go by

Ever loyal always ready to wag a tail on your arrival