Making Myself Invisible

If I could find or invent a way to make myself become invisible, I probably would as long ”it is not a permanent thing and i can control when I want to be and when I do not want to be invisible. I think I would use my new gift for good and try to help as many people as I can in my family, friends or just in this world in general. But if I had the opportunity to haunt someone i think it would be an ex of mine. the reason why would be for my own funny reasons and payback for all of the hurt he caused me during our relationship. I would not do anything to hurt him physically but i would play many tricks on him and make him think that he is crazy . lol