Hi Gail Simone. I want to create a superhero, but I feel intimidated, since my idea is pretty similar to some of Marvel new movies (expecially Ant-Man, which I didn't knew nothing about until the movie came out). Have you ever felt something like this? Of

I am not sure what you mean by ‘similar ideas.’ If you mean your character shrinks, that idea belongs to the world, really. Ant-man was far from the first character to have it. If you get into similarities beyond that, yeah, it could be a problem. 

My advice for all pro writers is this, if you are writing something and it feels like something that already exists, REWRITE.