To promote the release of the 18th Pocket Monsters Movie The Archdjinni of Rings: Hoopa and the 18th movie short Pikachu and the Pokémon Musicians, a rhythm game app called Dance? Pokémon Musicians (おどる？ポケモンおんがくたい) will be available for Apple iOS and Android for a limited time. The app involves players tapping to the music of Gaogao All Stars by Little Glee Monster, the theme song to the short "Pikachu and the Pokémon Musicians" and the current ending theme for the Pocket Monsters XY anime.

The app's release was on June 30th, 2015 and is free. It can be used on devices with iOS 7.1 or later or Android OS 4.4 or later. The app requires about 80MB of space to install, in addition to about 250MB of space while playing. It is also recommended that the app is played where Wi-Fi internet access is available. The app will be available to download until September 30th, 2015 and the apps service will end on October 29th, 2015.

Screenshots

'Dance? Pokémon Musicians' App - YouTube Trailer

Sources: http://www.pokemon.co.jp/ex/pokemon_ongakutai/, https://play.google.com/store/apps/details?id=jp.pokemon.android.odopoke and https://itunes.apple.com/jp/app/odoru-pokemonongakutai/id993993700