I was in the Battle Maison, cleaning up a battle, when a Vigoroth used Endure. Wow, he must be really scared of me. Then his Piloswine partner used Hail.
Now, let that sink it. Hail, after the partner uses Endure.
Edit: I just had a Talonflame that Will-O-Wisped it's Granbull partner. Probably a good thing, since it was a very hard battle. I had the Attack on my Slaking reduced by 3, had my Mega Audino poisoned by Sludge Bombs, had Accuracy reduced, and had to deal with Swagger and Thunder Wave shenanigans.
Very frustrating battle. That was my 28th battle so far. It came down to my Muk, and she won it for me.