Cosmog is a Legendary Pokémon which was obtainable by opening 20 out of 24 doors during the Advent Calendar 2016. Hatching a Cosmog egg would not count towards your shiny chain.
After unlocking the new Alola area for Rumbling, it is possible for Pokémon to find Nebula Stones there, with which you can find Cosmog eggs in the Tall Grass. As a result, it is now possible to shiny-hunt Cosmog.
In ages past, it was called the child of the stars. It's said to be a Pokémon from another world, but no specific details are known.
||EXP to level 100: 1,250,000
|Egg group: Undiscovered
|Gender Ratio: |
Male: 0% ......Female: 0%
Cosmog evolves into Cosmoem starting at level 43, which evolves into either Solgaleo or Lunala starting at level 53 depending on the time of day.