Anyone who has managed to obtain every regional (by traveling, trading, or any other means), every ... The Mystery Box can be activated by transferring a Pokemon from Pokemon GO to Pokemon Let's Go ...

Each transition requires both candy and a special evolution item. The candy is a common requirement across the game, but these evolution items are rarer.

Taking a look at whether shiny Ferroseed is in Pokémon Go, along with the shiny Ferroseed rates and perfect Ferroseed IV stats.