Pokémon Go is getting a new batch of monsters to collect, and it starts this Halloween. As part of its in-game event, which kicks off on October 20th, Pokémon Go will introduce a handful of new creatures, including Sableye, Banette, and what developer Niantic describes as “a few other ghost-type pokémon.” But the Halloween event is just the start. The developer says that the wave of additions will continue starting in December, with brand-new creatures pulled from Pokémon Ruby and Sapphire.

The Halloween event, which ends on November 2nd, will also include a handful of other new, temporary additions. Certain pokémon, particularly ghosts like Gastly, will be more abundant, and you’ll be able to catch a Pikachu wearing a witch’s hat. You’ll also be able to get a Mimikyu-themed hat to dress up your trainer.

The news comes a year after Pokémon Go introduced in-game events with its first Halloween celebration. Since then, the augmented reality game has continued to grow and expand in an attempt to keep players coming back. In the summer Niantic debuted new co-operative raids, and the developer has also added hard-to-catch legendary pokémon like Mewtwo to the game.

Other long-promised features are also still in the works, according to the studio. Back in July Niantic boss John Hanke told The Verge that there are “things we still want to have, like player-versus-player and trading.”