Let’s say that you are a famous rapper. You’re known not only for your music, but also for the dance moves that you popularize in your music videos. One in particular has gone viral - it’s a distinctive series of kicks and arm wiggles that you call the Billy Stone. You state the dance move’s name every time you do it - “Do the Billy Stone,” you say. You make a little money and take some time to enjoy your success: relax, hang out with your friends, play video games.
Let’s say you’re playing a particular online multiplayer roleplaying game. In this game, you build a character and use them to fight against other players. The game itself is free, but you can spend real money to buy cool upgrades for your character - new costumes, unusual weapons, and… dance moves. You scroll through the available dance moves you can buy for your character and lo, you see the Billy Stone. The game calls it the “Zilly Pebble” and charges five dollars for it.
You are pissed. You never gave anyone permission to use the Billy Stone, and you know that this game has made almost two billion dollars from in-game purchases in the last year. You call your lawyers. Do you have a case?
Maybe. It is possible that you could claim a copyright over this dance move, but you have several hurdles that will slow you down. The first is a copyright principle called fixation - in order for any creative work to be protectable by copyright, it must be fixed in a tangible medium, and no dance move is fixed on its own. Dances - or, as the Copyright Office calls them, “choreographic works” - can be fixed in two ways: they can be written down in choreographic notation, or they can be recorded as a video or a series of images. You’ve got this hurdle covered - your music videos contain plenty of instances of you performing the Billy Stone. But the next hurdle may throw you.
In order for a work to be copyrightable, it must also be minimally creative; that is, long and complex enough to warrant copyright protection. The Billy Stone may not be able to pass this hurdle, because it’s just a short series of moves intended to be performed by anyone, rather than a complex arrangement intended to be performed by a professional. The Copyright Office specifically excludes this type of dance from copyright protection: “Registrable choreographic works are typically intended to be executed by skilled performers before an audience. By contrast, uncopyrightable social dances are generally intended to be performed by members of the public for the enjoyment of the dancers themselves." The Billy Stone is simply too short and too casual to be eligible for copyright protection, and even though you may hold copyrights over your music videos and the depictions of the Billy Stone therein, those copyrights cannot prevent other people from performing the Billy Stone. You can prevent others from copying the videos themselves, or any portion of the videos, but you can’t stop someone from acting out the dance within the video.
But that doesn’t mean you don’t have a case, and your lawyers may need to get creative. You may not be able to copyright the Billy Stone, but that doesn’t mean you can’t trademark it. A trademark is defined by the Lanham Act as any “word, name, symbol, device, or any combination thereof” that is used in commerce to distinguish goods from other, similar goods and identify the source of those goods. Almost anything can be a trademark, so long as it is used to identify and distinguish a product - ad jingles and short tunes, phrases, even colors and smells have all been trademarked. You could make an argument that the Billy Stone is distinctive among your consumer base and identifies a song or creative work as something that came from you, and the fact that you call this dance move by name every time you perform it - “Do the Billy Stone” - gives this argument weight. You could then argue that the video game’s knockoff version of your dance - the Zilly Pebble - is confusingly similar to the Billy Stone, and likely to create a presumption among consumers that you are affiliated with or endorse this video game.
Trademarks and copyrights are a little different in how they are enforced, and this difference will be helpful to your strategy. If something is copyrighted, no one else can copy it at all, regardless of whether they profit from their copying. But if something is trademarked, you can only prevent others from copying it for a commercial purpose. This means that your fans, people at your concerts, and randos on Instagram can all do the Billy Stone without worry of legal ramifications, but the minute some video game developer starts charging five dollars to purchase it online, your mark has been infringed. This is notable because the Copyright Office’s justification for refusing copyright status to short “social” dance moves is that to do so would stifle creativity - reframing the Billy Stone as a trademark would only stifle creativity among corporate, profit-driven entities, while allowing fans and civilians to show their appreciation.
There’s no guarantee that such an argument would work, but when it comes to difficult disputes like this one, legal creativity can pay off. If you have an unusual problem, talk to a lawyer who isn’t afraid to get creative.
 With some exceptions, see 17 U.S.C. § 107.