The fact everyone on /vp/ was freaking out about this thing had me primed – it's not impossible that, had I gone in blind, I would've been BTFO, but I had been planning to play through the game with an Eviolite Munchlax anyways, and it pretty much walled it and after Mantine Toxic'd it, RestTalk BTFO Ultra Necrozma.
I had a Curse Banette ready and waiting as soon as it killed my Necrozma, but it wasn't necessary.
Nuzlocke is retarded. A more interesting way to make the game 'difficult' is to just raise shitmon you've not used before in game and aren't as familiar with, delay evolution and use Eviolite instead of evolving once you're clearly starting to fall behind, etc.