Pokémon Scarlet and Violet have announced a series of Tera Raid Battles featuring four rare shiny Pokémon: Wo-Chien, Ting-Lu, Chien-Pao, and Chi-Yu. These creatures will appear in 5-Star Raids, but players won’t be able to catch them.
However, if one million of each are defeated, players will receive a Mystery Gift containing a shiny version of the respective Pokémon. The shiny Pokémon will appear during specific event periods:
* Wo-Chien (Grass Tera Type) from July 23 to August 3
* Chien-Pao (Ice Tera Type) from August 4 to August 17
* Ting-Lu (Ground Tera Type) from August 18 to August 31
* Chi-Yu (Fire Tera Type) from September 1 to September 4
Players can still obtain these Pokémon by reaching the one million defeat mark before each event period ends. The shiny Pokémon will be rewarded for hitting this milestone, but they won’t be available for catching during the events.
Source: https://nintendoeverything.com/pokemon-scarlet-and-violet-announce-tera-raid-battles-with-shiny-wo-chien-ting-lu-chien-pao-chi-yu