>>38139956Intimidate, Stealth Rock, Ground immunity, U-Turn, super-wide moveset so it can choose to shit on any one of its checks, but kept in check by its 4x Ice weakness, Z-Fly as its only reliable and powerful Flying-type move, and only having Rest for recovery (read: no Roost) enough that it's allowed in OU.
Really, it might not even be as much overpowered as much that it can play an obscenely wide number of niches, and well.