Pokémon Sleep to host Mewtwo encounter event in September 2026

Pokémon Sleep announced a special event slated for September 2026 where players can encounter the Legendary Pokémon Mewtwo on Greengrass Isle, including an Expert mode version of the island. During the event, Psychic‑type helper Pokémon are especially effective, and the Mythical Pokémon Mew is expected to assist in researching Mewtwo’s sleep styles.

A parallel New Moon Day event will continue each month before the main event, allowing players to meet Mew. Developers are considering a feature to prevent friendship points earned with Mew during New Moon Day from being wasted when befriending Mew. The event’s main skill, Psystrike (Berry Zone), creates a Berry Zone that boosts energy from certain berries and persists until the player moves to a new location.