Apple is already being sued over one of the iPhone X's features

The iPhone X isn't even out yet and Apple is already being sued over one of its biggest features.

A developer is suing Apple for copyright infringement, alleging that Apple stole the "Animoji" name from the developer's app of the same name.

"This is a textbook case of willful, deliberate trademark infringement," reads the complaint, which was flied in federal court in San Francisco Wednesday.

The Animoji app, which has been in the App Store since 2014, allows people to send animated texts to friends via iMessage and other messaging apps. In the suit, Emonster kk, the Japanese company behind the app, alleges that Apple was fully aware of its app and the name, which is trademarked.

Apple declined to comment, but the lawsuit describes a pretty aggressive fight over the trademark.

Emonster kk says Apple began trying to buy its trademark in the summer of 2017. That's when, according to the suit, Animoji's creator Enrique Bonansea was approached by a series of companies with names like "The Emoji Law Group" who tried to buy the trademark and "threatened to file a cancellation proceeding if Bonansea did not sell the mark."

Bonansea believes that Apple was really behind these groups. A day before Apple's iPhone X event, one of these groups filed a cancellation request with the U.S. Patent Office.

Interestingly, Apple's use of the "Animoji" name may have ended up helping the app -- at least in the short term. The app, which has only seen about 10,000 downloads overall, saw a sizable bump in downloads in September around the time of Apple's iPhone event, according to data from Sensor Tower. The increased downloads were likely the result of people searching for Animoji following Apple's keynote.

Still, the company says its business has suffered since Apple's launch -- both because its app is no longer the top search result for "Animoji," and because they're now having to rush out their next update.