The frosty creature, Kyurem, has returned to Emera Town and stays until February 10th. As always, it is searching for trainers who express their love for Pokémon by interacting a lot. Every interaction you do gives you a random chance of encountering Kyurem. Plus, as a special incentive for every trainer who has already met it before: Instead of receiving a Kyurem egg, you can now choose to receive Kyurem Plushies instead. Claiming these plushies will slowly raise your Kyurem Shiny Chance!
Check out the forum news post linked below for a detailed description of the event and an FAQ.