Answer:
I am a caribbean shape that makes ships disappear
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.
Always in you, sometimes on you. If I surround you, I can kill you. What am I?
If two is company and three is a crowd, what is four and five?
I am a protector. I sit on a bridge. One person can see right through me, while others wonder what I hide. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.