Via the official Pokémon GO newsletter, Niantic has confirmed that another Halloween-themed event is just around the corner. According to the newsletter, Professor Willow has noted that spooky things have been happening and may be related to Ghost-type Pokémon. The event will take place later this month after the Psychic Spectacular concludes. Full details have yet to be announced, but stay tuned for any updates. The first announcement from the development team is as follows:
Trainers, some breaking news! Professor Willow is reporting that some spooky happenings are going on nearby. Could it be the work of Ghost-type Pokémon? Stay tuned to find out!
Source: Pokémon GO newsletter