Answer:
I am a caribbean shape that makes ships disappear
They are many and one, they wave and they drum, used to cover a stare, they go with you everywhere.
Lighter than what I am made of. More of me is hidden than seen. What am I?
What can travel all around the world without leaving its corner?
I plow and plow but never sow.
No matter how little or how much you use me, you change me every month.