It's common sense for Pokémon fans that shiny Pokémons are extremely rare Pokémons that differ in coloration from their regular appearance. Hence, these "one of a kind" mutated Pokémons became extraordinary collectibles in all Pokémon installments.
Recently, a player found a shiny Geodude in Pokémon Sleep when unpacking the game.
Oh, there's shinys in Pokémon Sleep pic.twitter.com/BvHn5j5ryI
— Eevee (@ElChicoEevee) July 10, 2023
Unlike other previous Pokémon games, Pokémon Sleep is an upcoming sleep-tracking app that rewards the user with Pokémon depending on the quality of their sleep. It is scheduled for release on Android and iOS in late July 2023. Android users can preregister the app.
Source: Twitter