https://www.polygon.com/2018/9/22/17889718/pokemon-go-new-mystery-pokemon-891-ditto-chikorita

Something very strange happened in Pokémon Go today at the conclusion of a scheduled community day event: A mysterious, never-before-seen Pokémon spawned in the game, leading to confusion and speculation about what it means for Niantic and The Pokémon Company’s mobile title.

In the Asia-Pacific region, at 3 p.m. in Japan, Pokémon Go’s community day event focused on the Pokémon Chikorita came to an end. Suddenly, the world of Pokémon Go was densely populated with a new type of Pokémon, one that looked like a white Ditto with a hexagonal nut for a head and a single eye at its center. When a player caught the new Pokémon — which appeared with the name “???” and a Combat Power (CP) rating of “???” — it would turn into a Ditto, typically an uncommon, harder-to-find Pokémon.