The Ultra Spooky Cup is currently underway in Pokémon Ultra Sun and Ultra Moon, featuring eerie Ghost-type and Dark-type Pokémon, as well as others who fit in with those sinister types. Trainers are limited to 15 battles per day, with unplayed battles carrying over to the next day. All qualified participants in the Ultra Spooky Cup Online Competition will receive a Shiny Mimikyu. Players must complete at least three battles to qualify. You’ll be eligible to receive a Shiny Mimikyu whether you win or lose, so have fun out there! The competition ends on Sunday, October 28, 2018, at 23:59 UTC. The results will be posted shortly after the competition has completed. Check out the Ultra Spooky Cup regulations page for complete details on this fun event. If you missed the opportunity to compete this time, check back at Pokemon.com and the Pokémon Global Link for future competitions.
Source: Pokémon Global Link