Originally shared by Pokémon GO
We also have another special treat for you. Starting later today through December 29, 2016, 10:00 A.M. PST, you’ll find limited edition Pikachu all over the world. These Pikachu will be wearing a festive hat to celebrate the season! Use the Pokémon GO AR camera when you encounter them in the wild to take their picture and share it with us using #HolidayPikachu.
—The Pokémon GO team