Turn 1: Set up Spikes as either your opponent KO's you or switches out. Regardless, the damage is done; they can no longer switch without auto-losing. If they switched, burn a turn while they KO you (both Arceus and Zekrom will die before they KO 3 pokes due to LO recoil, and once they die from recoil you auto-win due to hazards) and if they KO'd you, switch to Forretress. Switch to-and subsequently sack-Mewtwo, which allows you to switch Forretress in again. You are now withing Custap Range, which means that you can KO Kyurem-W with Gyro Ball. Case closed.
"May the odds be ever in your favor"
"WTF HAX NOOB"
The hills are alive with the sound of PS ladderers.