Showed up around Halloween, about two years ago. These assholes who called themselves Teams Aqua and Magma had summoned a couple legendary Pokemon to wreck everything - and they still thought they were the good guys, if you'd believe it, it was a huge pain. But then Arceus showed up and stopped them, and he did some stuff to fix everything they'd broken, and pretty much a day or so later, Rose pulled me away excitedly to show me that she was suddenly immune to dragons.

...Her and about half a dozen members of my team.