This page covers sparkling Shiny Pokemon in Pokemon Rumble rush, including what they are, and how to find them.
As of now, Pokemon Rumble Rush does not include Shiny Pokemon in the traditional sense, but you may see “shiny” Pokemon that sparkle when playing through a stage.
These sparkling Pokemon are guaranteed to be caught if killed, so make sure to prioritize these if you see them.
As of now, it seems like these Pokemon’s appearances are random, and there’s nothing you can do to increase their spawning. Just see them as lucky encounters!