By now, you probably have heard of the infamous “left shark” in Katy Perry’s Super Bowl XLIX halftime show, who went off script and did its own moves during “Teenage Dreams” and “California Gurls.”

So much buzz built about the shark that a 3D printing service, Shapeways, starting offering Left Shark models online, which prompted a letter from Perry’s attorneys insisting that the service stop sales immediately, claiming that the shark character was protected by copyright.

Shapeways sent a response stating that it did not appear that Perry owned the copyright for Left Shark (because a copyright is owned by the “author,” in this case the costume designer, and she did not design the costume), and that she had no basis because courts have held that costumes are useful articles and, thus, ineligible for copyright protection.

But wait! Though a costume may be classified as a useful article, courts also have held that design elements that are separate from the function of “clothing” are eligible for copyright. In fact, the U.S. Copyright Office lists a registration for “Shark costume; Children’s shark costume” (VA0000624682) owned by the Children’s Museum of Indianapolis.

Whether Perry does, in fact, own the copyright is yet to be determined, but this exchange is a lesson for business owners who send cease-and-desist letters without thinking about the consequences. In the past few days, the Internet has spiked with anti-Perry comments, and the model has been downloaded more than 11,000 times. Probably not the result Perry desired.