What do you call a cheese that isn't yours?

I'm the court's fool, yet wear no crown, but my smile can bring a kingdom down. What am I?

What you might here at the top of a beanstalk

I have skin but no bones, a mouth but no teeth, and I swallow your secrets while hanging from your arm. I sometimes have a hand in me, I also have a hand in my name. What am I?

Sharp little teeth, yet no bite from me, I shed your blocks like falling trees. Across my face you push with care, Till tiny strands are everywhere.