The Pokémon you encounter in Pokémon Go come and go throughout the many events and seasonal challenges. It’s hard to keep track of nearly 600 Pokémon and remembering where they come from. For those on the hunt for Alolan Raichu, this one is an obvious answer, but it makes it even more difficult to locate. You cannot evolve a Pikachu into an Alolan Raichu, dispute the Alolan Pokémon being the evolved form of the Electric-type Pokémon mascot. Instead, the only way to encounter and find this Pokémon is to find it at one of the raids, beat it in a battle, and then capture it at the end. The Pokémon does have a chance to be a shiny version.
If you’re trying to find an Alolan Raichu in the wild, that doesn’t work either. When Alolan Raichu was initially released to Pokémon Go, Niantic made it strictly a raid Pokémon. It’s similar to many of the other Alolan or Galarian Pokémon that have appeared in the game, such as Galarian Stunfisk, Galarian Zigzagoon, or Alolan Exeggutor.
These Pokémon are special, different from their original forms, and in some cases, more powerful than their regular forms. That’s the case for the Alolan Raichu, at least. It’s stronger than the regular Raichu form that Pikachu evolves into. Alolan Raichu is an Electric and Psychic-type Pokémon. It has different stats and a unique moveset. However, despite having different moves, they share enough of the same ones to have similar attacks. Another big difference is Alolan Raichu is resistant to Psychic and Steel-moves, but it’s weak to Ghost, Dark, and Bug-type attacks.
The only way to catch Alolan Raichu is to capture it in a raid. You can access these raids using raid passes, and you regularly find Alolan Raichu appearing in several events. This Pokémon rotates out of these events pretty frequently, so you may have to wait a few months for it appears again.