Halloween Event announced with Gen III Ghost Type and Candy bonuses starting from 20th October

Trainers,

Looks like the Halloween came too early and will be lasting for 13 days. Pokemon GO Officially announces the Halloween event starting from October 20 at 12:00 P.M. PDT and run until November 2 at 1:00 P.M. PDT.

SUMMARY OF THE EVENT – Halloween treats!

Event Period: From October 20 at 12:00 P.M. PDT and run until November 2 at 1:00 P.M. PDT.

Visit PokeTimer – To view your Local Start Time
Click here to view Time remaining for the Event Start

New Pokemon: Sableye, Banette, and a few other Ghost-type Pokémon originally discovered in the Hoenn region

And A special Pikachu celebrating Halloween in an all-new costume.

Increased Spawn: All spooky Pokémon

Special Rewards:

1. 2X Candy for catching, hatching and transferring Pokémon.
2. 2X Candy from Buddy Pokemon.

Avatar: Mimikyu’s Disguise Hat for Avatar

Game Shop Discount: Special Boxes featuring items like Raid Passes and Super Incubators.

Here’s the Official Statement from Niantic

Gastly, Drowzee, Cubone, and other spooky Pokémon are back again this Halloween, and this time, they’re bringing some special friends! Sableye, Banette, and a few other Ghost-type Pokémon originally discovered in the Hoenn region will be making their first-ever appearance in Pokémon GO. The rest of the Pokémon first seen in the Pokémon Ruby and Pokémon Sapphire video games will gradually arrive starting as early as December! We hope Trainers enjoy this special Halloween treat. The Halloween celebration will start on October 20 at 12:00 P.M. PDT and run until November 2 at 1:00 P.M. PDT.

A special Pikachu will be out celebrating Halloween in an all-new costume, and you can, too! Dress up your avatar for the occasion by wearing Mimikyu’s Disguise Hat. You’ll also earn extra Candy while you’re out trick-or-treating with your Buddy Pokémon: Candy rewards from catching, hatching, and transferring Pokémon will be doubled, and your buddy will find Candy twice as fast during the Halloween celebration! Last but not least, you’ll have the opportunity to stock up for your upcoming adventures with special boxes from the in-game shop, featuring items such as Raid Passes and Super Incubators.