Planet Karaoke was a planet once visited by the Twelfth Doctor and Clara Oswald. (COMIC: Day of the Tune, The Meddling of Clara's Song, One! Two! Three! Four! To Doomsday)
The natives of Planet Karaoke spoke Karaokean. (COMIC: The Meddling of Clara's Song)
When the friction contrafibulator needed repairs, the Doctor set down on Karaoke. This meant shutting down the translation circuits. (COMIC: Day of the Tune) Not hearing this, Clara tried her hand at singing but without the translation circuits instead insulted the planet's monarch so badly that she got herself and the Doctor arrested. (COMIC: The Meddling of Clara's Song)
Given a chance for their freedom, the two were set to perform on Battle of the Bands Beyond the Stars, only to discover that five incarnations of the Master had co-opted the show. (COMIC: The Abominable Showmen) After the Master's ego had led to their incarnations arguing over which one should rule the galaxy and they were disqualified, (COMIC: The Five Masters) Clara and the Doctor made their way onto the stage, where Clara simply cut the operation's power, killing the show's ratings, before the two ran back to the TARDIS, flying off to get some chips. (COMIC: One! Two! Three! Four! To Doomsday)