It’s a GameStop joint
Nintendo and the Pokemon Company are starting off the 2018 “Legendary Distribution event” today with Dialga and Palkia. Just like the original anniversary celebration each month will see a new legendary, but this time they’re doing it in pairs.
You can pick up the aforementioned legendary duo until February 28, and each copy of Pokemon can net one. In other words if you have multiple copies of Sun, Moon, or either Ultraedition you can get them both.
This one is live at GameStop and EB Games locations in the form of a distribution code. Next month will see Regigias and Heatran.