Gastly, the gas Pokémon from Kanto, can be found in the wild in Pokémon Go. Yes, Gastly can be shiny in Pokémon Go!
Though its shiny version is pretty disappointing, Gengar is very meta when it comes to ghost- and poison-type moves. It’s propelled even further by its Mega form, which sits happily on the top of the poison-type attacker DPS charts (for now at least).
What is the shiny rate for Gastly in Pokémon Go?
As per old research by the now-defunct website The Silph Road (via Wayback Machine), the shiny rate for Pokémon on a regular day is approximately one in 500. Gastly is not a confirmed Pokémon that gets a “permaboost” (meaning that it’s a rare spawn and thus gets a boosted shiny rate).
What can I do to attract more shiny Pokémon?
Not much, unfortunately. It appears to be random chance. Shiny Pokémon catch rates are set by developer Niantic, and they are typically only boosted during special events like Community Days or Safari Zones, or in Legendary Raids. There are no consumable items that boost shiny Pokémon rates.