Moveset:
Sheer Cold, Lock On, Double Team, Cosmic power.
The Sheer Cold, Lock On duo to kill em off.
Double Team, Cosmic Power help to keep you alive.
Hold Item: Leftovers (regain your health, effective if they can't hit you because of Double Team and do little damage because of Cosmic Power)
OR
Focus Sash (So they can't kill you in one move in between your Lock On and you OHKO)