Pokemon Sleep is adding the thunderous Legendary Raikou to its line-up. Fans didn’t know what to make of Pokemon Sleep when it was first announced back in 2019, as The Pokemon Company only gave a proper explanation for what it was shortly before its release last summer. As its name suggests, Pokemon Sleep is a mobile app that tracks a player’s sleep patterns and allows them to unlock different Pokemon by simply having their phone next to them while dozing off for the night.