A recent Pokémon GO datamine suggests that Darkrai may be the Halloween 2020 event raid boss. This certainly comes as a surprise to Pokémon GO trainers, and perhaps not necessarily a welcome one.
The dataminers known as Pokéminers discovered Darkrai's signature move of Dark Void added to the game. That happening directly before the Halloween 2020 event is suspicious and may mean that Darkrai will, once again, be the raid boss for the spooky season.
This may come as a disappointment to Pokémon GO trainers if true. Niantic referred to the boss that will take Giratina Origin Forme's place on October 23rd as "a special Raid Boss that'll be available to challenge during our Halloween event!" This will come as a disappointment to many, as Giratina was a huge Shiny release and this bit of text, as well as the hype around the Halloween event every year, suggests that the next boss will be an even bigger deal than Giratina. Darkrai already has its Shiny form and was featured in raids twice this year. It was even available through GO Battle League.
Speculation of the Halloween raid boss included Yveltal for a Generation Six rollout and Mewtwo, which has been long-absent from raids. Featuring a boss that has been as available as Darkrai during the biggest event of the year will be a rare miss for Niantic, a company that has, despite what you'd see on social media, given the world's biggest franchise new life in the dynamic and enjoyable Pokémon GO.
Now… datamined information generally does come to fruition in Pokémon GO. However, it does not always come to fruition imminently. All of this to say, Darkrai may not be the Halloween 2020 boss. In fact, Niantic may have even added its exclusive moves to throw dataminers off of their scent in order to keep a bigger surprise for the event under wraps. It could even be part of a Halloween Raid Day rather than the full event's boss. Because of all this, it is worth it to give Niantic the benefit of the doubt considering the success of their previous Pokémon GO Halloween events, and trust that, hopefully, they have some spice planned for the raids.