Insomnia Gourgeist Set
EVS: Attack 252, Spe 252, HP 4
Alright so personally I had another set planned for this 'mon but uhm... it didn't work out cause I later found out it had hidden ability and so then I decided to go along with Insomina. But anyways this 'mon is not affected by yawn and has a good move pull. Shadow sneak is used a decent amount so I figure it isn't a bad choice here. And leftovers gets you some nice HP every turn.