What is the rarest pokemon in pokemon go?

Here's some information about the rarest Pokémon in Pokémon GO:

Determining the absolute "rarest" Pokémon is tricky as availability changes frequently due to events and game updates. However, considering factors like limited availability, region-exclusivity, and low spawn rates, here are some generally considered to be among the rarest:

• Shiny Regional Pokémon: Regional Pokémon are already limited to specific geographic areas. Shiny versions of these regional Pokémon can be extremely hard to find, due to the low shiny rate and the limited region. Examples include Corsola (tropical regions), Heracross (South America, Central America, Florida), and Tropius (Africa and parts of the Middle East).

• Unown: Unown, appearing in various letter forms, typically only spawns during special events or in very specific locations. Finding all forms of Unown is a major accomplishment.

• Meltan and Melmetal: While Meltan is available through Mystery Boxes from Pokémon HOME/Let's Go, requiring consistent linking and transfers between games makes obtaining it, and especially evolving it into Melmetal, a time-consuming process.

• Galarian Mr. Mime: This Pokemon was mainly available during special events with paid tickets. It hasn't been widely available outside of these events, making it rare for players who missed them.

• Shadow Pokémon from Giovanni: Every month, Giovanni appears with a new legendary pokemon. Getting all of them requires continuous playing.