Okay, I have an idea, though not sure if it would exactly be viable, or original. And definitely wouldn't work in Wifi, but essentially all you need is Cofragius and Slaking on the same team. Use Cofragius to try and take out a pokemon using whatever moves you choose. Maybe cripple them in some way with Toxic/WoW. The main selling point would be transferring Mummy over to them, and then using Memento as a last ditch effort. With both Mummy AND attacking stat drops, they are definitely going to switch. Then, Pursuit Slanking, whatever set you want, Bob's your uncle.