During PM2023 42, which aired in Japan on March 8th, 2024, a special First-Airing Segment aired with Professor Willow. A passcode was originally revealed during that segment that allowed players of Pokémon GO to obtain Captain Pikachu in a Bonus Timed Research.


Official Twitter Post:
The official Pokémon GO Twitter account posted a Tweet announcing the code shortly after the episode finished airing.

Celebrate Pokémon Horizons: The Series with Pikachu wearing Cap's hat in Pokémon GO! Enter the code CAPTAINPIKACHU on the Pokémon GO website to activate this encounter. The offer code and Timed Research expires on March 13th at 11:59 p.m.

Source: https://twitter.com/PokemonGoApp/status/1766048721974772112