Ruins of Conflict Tapu Koko .

In Pokemon Sun & Moon, the battle with Melemele Island Guardian Tapu Koko is a forced battle in the credits after becoming Champion.
The Pokemon Ultra Sun & Moon, Tapu Koko can similarly be found at Ruins of Conflict, when the players chooses to do so after becoming Champion.
After the battle, the player will pick up the Tapunium Z.

This encounter cannot be shiny. Details below refer specifically to this file.

Species   Tapu Koko   Nickname   (default, in )   OT   PPorg   TID   171117   Distribution   In-Game Encounter   Location   Ruins of Conflict   Dates   Nov 18, 2017   PID   Cannot Be Shiny   Games   Ultra Moon

Lv. 60

Nature   Jolly   Ability   Electric Surge (1)   Item   None

Moves   (ITALIC means Relearnable)   Nature's Madness   Discharge   Agility   Electro Ball

Format Ver.1.0.5-5, Post Updated Date:20171122_2255