Earlier this year, Apple spun off the viral late-night show skit “Carpool Karaoke” to a full-blown TV show exclusive on Apple Music. The show received mixed reviews critically and never took off commercially.

But it turns out, Apple was sitting on a gold mine of a karaoke show all this time.

New iPhone X users have been uploading to social media karaoke songs of themselves using the new Animoji feature. Animojis are custom animated characters that use the user’s voice and mirror facial expressions in the Messages app.

Tweets of floating, virtual animal heads on a white background singing Queen’s “Bohemian Rhapsody” or AC/DC’s “TNT” quickly have gone viral, garnering thousands of retweets and likes.

There are boatloads of fun content on Twitter under the hashtag AnimojiKaraoke. And of course, there are spin­offs into AnimojiTheater, where Animojis re-enact famous movie scenes.

Many observers have lauded Animoji as an underrated breakthrough in the new iPhone X, with some comparing the feature to Snapchat filters and musing about its potential.

For those who want a slice of Animojis right now, you will have to get an iPhone X. The ability to mimic a user’s facial expressions is from the same suite of new front-facing cameras and sensors that are used for Face ID.

But there may be a wrinkle to the future of Animoji. In October, a Japanese company called emonster k.k., which owns the trademark for “Animoji” in the United States, sued Apple, alleging trademark infringement.

Emonster k.k. and its owner, Enrique Bonansea, claim that their Animoji app was available on the iOS App Store and that Apple offered to buy the trademark. When emonster k.k. and Bonansea turned down the offer, the lawsuit said, Apple proceeded to use the name anyway.

“Instead of using the creativity on which Apple developed its worldwide reputation, Apple simply plucked the name from a developer on its own App Store,” the suit said.