Someone new in the scene ripped off my burlesque routine I've been doing for almost 4 years. What should I do?
Try contacting them and asking them about it, to be sure that they're ripping it off and not just responding to the zeitgeist. If you're already sure or not satisified with their response, keep doing it better, post more pictures and video of it, and file a cease and desist if you think it's warranted. And let people know if you think someone else is an intellectual property thief--you do no one in the scene a favor if you let them keep hiring an unethical performer.
I have been ripped off a bit and have had people feel entitled to my intellectual property. It's interesting as a teacher, where someone who has taken my class will teach a class that is essentially the same and then say that it's not a rip off because I didn't invent burlesque, ignoring the fact that I manage to work with burlesque teachers from all over the world without feeling that they are compromising my intellectual property. I'm a fan of The Art of War, which means I try to think of all the possibilities and think a few steps ahead. But I will engage in a fight at times. You owe it to your muse to defend your art and your ideas, and you owe it to that person's muse to force them to call on their own instead of on yours.