It's Dialga

It also shows up as a splash page on everyone's Pokemon Go account

I am so sad.
Not because of Dialga but because this means the lake trio will very likely not be spread apart from each other.
*shrug*

I just hope that they have a better spread of Raids out there this month. Where I am, it's been 75% Legendary Raids, 25% Levels 1-4. (Still a bit salty; only saw a single Dragonite raid at a time and gym I couldn't do it, and I so wanted to get my Mamoswines out into a decent raid!)