Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Fairy Mold Breaker Azelf
I can already feel the rage from Mega Sceptile sweeps that come from a SpDef drop. Honorable Mention: Weak Armor Mega Garchomp
Fairy type Azelf + Mold Breaker because Sceptile will probably cause ragequits and anger. Honourable Mention: Weak Armour Mega Garchomp (I'll vote this until it wins lol)