Answer:
who do you think you know but sometimes you don't
I build up castles. I tear down mountains. I make some men blind. I help others to see.
When they are caught, they are thrown away. When they escape, you itch all day.
My voice is tender, my waist is slender and I'm often invited to play. Yet wherever I go, I must take my bow or else I have nothing to say.
Voiceless it cries, Wingless flutters, Toothless bites, Mouthless mutters. What is it?
What is so fragile that saying its name breaks it?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?