Pokémon Go's annual Halloween event begins this Thursday, 17th October at 9pm UK time (1pm Pacific).
It will feature the release of creepy new Gen 5 Pokémon Yamask, (which evolves into spooky sarcophagus Pokémon Cofagrigus), and which will be available Shiny.
Legendary Pokémon Darkrei will make its debut in Tier 5 raids, meanwhile.
There will be a new set of Special Research to complete, which will again reward the Halloween-exclusive Spiritomb.
And another round of Shadow Pokémon will be available from Team Rocket PokéStops: Weedle, Kakuna, Beedrill, Electabuzz, Magmar, Lapras, Mareep, Seedot, Nuzleaf, Sableye, Trapinch, Cacnea, Shuppet, and Duskull.
But perhaps the most eye-catching releases of the event are the new costumed forms of Pikachu, Bulbasaur, Charmander and Squirtle. These will be available in shiny forms as well.
Bulbasaur wears a Shedninja costume, Charmander wears a Cubone outfit, and Squirtle wears a Yamask hat. These will be available in raids - the first costumed Pokémon to be made available this way.
In the wild, you'll find Pikachu wearing a Mimikyu costume. Which is, of course, a little Inception-y - as Mimikyu is itself wearing a costume of Pikachu.
Lastly, there will be new regular research tasks, more avatar items, plus double candy when catching, hatching and transferring Pokémon.