One day of Halloween just isn't enough, and that's why the fun is starting early in Pokémon GO! From October 23, 2020, at 6:00 p.m. PDT (GMT –7) to November 3, 2020, at 6:00 p.m. PST (GMT –8), you'll be able to enjoy a handful of Halloween-themed treats, including the Pokémon GO debut of Galarian Yamask and its evolved form, Runerigus! This is the first time these Ghost- and Ground-type Pokémon will be available in Pokémon GO, so don't miss your chance to add them to your Pokédex!
Additionally, a menagerie of other spooky Pokémon will be appearing more frequently in the wild. Spiritomb, the Forbidden Pokémon, will also be featured in encounters rewarded for completing event-themed Field Research tasks. If you're lucky, you might even encounter a Shiny one!
It wouldn't be Halloween without costumes, and this year, you can look forward to costumed Gengar and Sableye wearing Litwick hats! But that's not all: for the first time, you'll be able to challenge Mega Gengar in Mega Raids, and raids featuring the Ghost- and Poison-type Pokémon will be happening more frequently for the duration of the event!
Finally, the Pokémon GO shop will be serving up more treats than tricks—the Special Box will become the Creepy Crate, the Ultra Box will be taken over by the Boo Bundle, and the Adventure Box will transform into the Pumpkin Pack. There will also be a number of new avatar items that you can use to dress up your avatar.
Keep it spooky out there, Trainers!