What To Use

Skarmory @ Leftovers
Sturdy
EVs: 252 HP / 232 Def / 32 Spe
Impish Nature
- Roost
- Whirlwind
- Spikes
- Brave Bird
Role: Physical Wall
What it does:
Ever since Skarmory's release in GSC, the metal bird has been one of the most prominent physical walls in the game. With his massive base 140 Defense stat, Skarmory can wall the numerous physical attackers in OU including but not limited to Scizor, Breloom, and Landorus-T. His Steel typing allows Skarmory to resist Dragon type attacks, putting a stop to the likes of Dragonite, Salamence, and Haxorus who could otherwise easily sweep through a team. Sturdy allows Skarmory to live any attack if he is at full health. Roost is a great move to provide instant recovery but users must beware of the fact that Roost removes Skarmory's Flying type for the remainder of the turn, making him susceptible to Ground and Fighting type attacks. Skarmory works as a great phazer with Whirlwind to negate any stat boosts and rack up entry hazard damage and the bird can set up some of his own entry hazards with Spikes. Brave Bird is a powerful STAB even with Skarmory's low Attack stat and prevents him from being completely shut down by Taunt. Skarmory is a combination of great physical wall, entry hazard setter, and phazer.
Good Teammates:
Special walls are the best partners for Skarmory so together they can wall most attacks the opponent tries to throw at them, the most notable being Blissey. Blissey's massive Special Defense bulk easily handles the special Fire, Electric, and Water attacks while Skarmory takes the physical Fighting attacks that would take out Blissey. Another great partner to Skarmory is Specially Defensive Heatran who is immune to Fire type attacks with his Flash Fire ability and so can switch into a predicted Fire type attack aimed at Skarmory and grab a free boost. Heatran also makes a great Stealth Rock setter to complement the Spikes Skarmory can set up. Specially Defensive Tyranitar also makes a good partner with his high Special Defense stat boosted by Sandstorm's effect. Tyraniatar handles threats to Skarmory such as Latios, Latias, and Starmie and Skarmory returns the favor by walling common threats to Tyranitar such as Scizor, Breloom, and Terrakion.
What Counters It:
Powerful Special Attackers are the primary counters to Skarmory, especially those that carry Fire and Electric type attacks including Latios, Heatran, and Jolteon. Due to Skarmory's low Special Defense stat and lack of investment even resisted Special attacks can break through the bird such as Tornadus-T's Hurricane. Magnezone is especially troubling as his Magnet Pull ability prevents Skarmory from switching out and he can easily take out the bird with his Electric STAB. Rain teams are troublesome some for the bird as he can not take Rain-boosted Water attacks and is severely crippled by Scald burns. Taunt users that are not bothered much by Brave Bird such as Deoxys-D can set up entry hazards in Skarmory's face and heal up using Recover. Forretress can Rapin Spin away all the Spikes Skarmory sets up while setting up his own hazards and hitting hard with Volt Switch.