To encourage preorders of Scarlet & Violet, we’ve learned GameStop stores will be holding a distribution for shiny Eternatus. It will take place for a limited time from September 18th to October 1st. Presumably it’ll be to Sword & Shield, as Eternatus isn’t programmed into BDSP or Arceus.
We have no further details on the distribution itself. It will presumably be announced in a week or two.
This is the first time there has been a distribution for Eternatus, let alone a shiny one. Eternatus is shiny-locked in the games, so this is the only way to get one.