Fortnite keeps stealing dances — and no one knows if it’s illegal
Here you go:
1. Copyright is created automatically upon creation of intellectual property (art, song, dance, book, etc.), you don't need to file anything.
2. To have a copyright created, the intellectual property, in this case a dance, has to be unique enough to basically be recognizable and distinct from other dances. So basically, unique.
3. That probably applies to The Carlton, the Thriller dance, and the Pennywise dance. And might apply to other dances depending on the facts.
4. If a company uses the dance without paying for it, they are likely to lose a suit for violation of the copyright. (There are defenses to copyright like fair use, i.e. satire, but if you use it to make money it's not a fair use and that is clearly what is being done here.)