On Saturday September 22nd 00:00 to Sunday September 23rd 23:59 BST all Ultra Beast Pokémon found on the maps will have twice their usual spawn rate.
Necrozma will be slightly more common than the rest on the Ghost/Psychic maps.
The following Pokémon will be more common during this period:
In addition to this, a previously unreleased Ultra Beast will be made available for these two days which will be named at a later date.
- Ultra Beasts can only be caught with either a Beast Ball or a Vortex Ball
- The newly added Ultra Beast will not be exclusive to this event - It will be a permanent addition on the maps in the next update (v4.2.x)