Leavanny power. I mean you could also try Yveltal and give it Block Smash+. The best sleep inducing ability is Nap Time because it can go off so easily although you need to make a match of a Pokemon capable of mega evolving that immediately triggers mega evolution (triggering Mega Boost+ works too). Even then, Darkrai is preferred over Venonat. Please replace Silvally with Hoopa Unbound if necessary. I know catching Hoopa Unbound is a long jourmeys ahead, but it will appear in the special stages someday. Oh, and make sure you activate Mission Card 9 before going any further...
