https://www.polygon.com/2018/10/28/18034600/pokemon-go-shedinja-event

Pokémon Go will celebrate bug types in November, a nice callback to the franchise's roots. In exchange for our bug-catching, players will have the chance to catch the rare Shedinja for the first time.

Shedinja will be the reward of completing a field research challenge sometime next month, according to the game's Twitter. This eliminates figuring out how to otherwise implement this little weirdo.