what is a shiny pokemon in pokemon go

A Shiny Pokémon in Pokémon Go is a rare variant of a Pokémon that has a different coloration than other Pokémon of its species. Shiny Pokémon can be encountered randomly in the wild, during special events like Community Days or Pokémon GO Fest, or through Raid Boss encounters, Special Research Breakthroughs, Research Task rewards, and other rewards. Shiny Pokémon have no advantages in combat or anything like that, and their only purpose is cosmetic and rarity. There is no reliable method to catch a Shiny Pokémon, and it's entirely up to chance.