I'd like to put forward my set. It's a bit unconventional, but I guarantee it works
Umbreon @ Leftovers
Ability: Syncronize
Nature: Impish (+Def, -SpAtk)
EVs: 120 HP / 220 Def / 168 SpDef
-Confuse Ray
-Toxic
-Assurance
-Screech / Heal Bell
Offensive Umbreon may sound like a bad idea, but...