Since the very beginning of the GSC metagame, Skarmory has proved to be a force to be reckoned with. With an amazing base 140 Defense stat, 9 resistances, 2 immunities, and no physical weaknesses, Skarmory is easily the best physical wall available in GSC. Throw in Skarmory's ability to phaze opponents with Whirlwind and boost its already ridiculous Defense with Curse, and you have an excellent check to top threats such as Snorlax, Marowak, Heracross, Exeggutor, Machamp, Umbreon, Quagsire, and Espeon. In addition, Skarmory's resistance to Normal-type attacks also makes it a good switch-in to most predicted Explosions.
While Skarmory is an amazing physical wall, it lacks the ability to effectively deal with special attacks from most special and mixed attackers, the reason being its measly base 70 Special Defense and poor base 65 HP. Skarmory's movepool is also rather limited; beyond Toxic and Drill Peck, it has little in the way of offense, and is forced to rely upon Rest and Leftovers for healing off damage due to its lack of recovery options. While sleeping, Skarmory will no longer be able to check some threats, such as Belly Drum Snorlax, Marowak, Machamp, and trappers, although others, such as Curse Snorlax, non-Seismic Toss Heracross, and most Exeggutor, still won't be able to get past Skarmory. That said, Skarmory is still an incredible defensive Pokemon that should always be considered when team building, especially when creating a stall-based team. Ignore this bird of steel at your own risk!
This set gives Skarmory everything it needs to succeed. With access to Whirlwind and Curse, as well as fantastic resistances, Skarmory will be able to counter many top OU threats with ease. It can easily come in on Curse or Belly Drum Snorlax and phaze it with Whirlwind. Curse allows Skarmory to effectively wall Belly Drum Snorlax as well as last-Pokemon Curse Snorlax after only one or two boosts. Skarmory can also deal with the likes of Heracross, Marowak, and Machamp, preventing them from sweeping or setting up. Additionally, it can serve as an effective check to Umbreon and Misdreavus without Thunder, as Whirlwind will stop their respective trap-passing and Perish-trapping attempts.
Curse gives Skarmory additional Defense boosts, increasing its general longevity. The sheer physical durability of Skarmory after a Curse cannot be understated. For example, at +1 Defense, Skarmory will almost never be 3HKOed by Snorlax's 999 Attack Double-Edge, 999 Attack Marowak cannot 3HKO with Rock Slide, boosted Steelix can't OHKO with Explosion, 999 Attack Rhydon never 2HKOes with Rock Slide, and Machamp will fail to OHKO with a +1 Cross Chop even with a critical hit. Curse also gives Skarmory a Speed drop that lets it phaze other Curse and Roar users, such as Steelix, Rhydon, and Tyranitar, that would otherwise phaze Skarmory instead. While not common, Skarmory can occasionally sweep thanks to Curse if Growl users and special attackers such as Zapdos and Raikou are removed, but this is a very situational scenario. A quick note on Curse: when using Pokemon Netbattle Supremacy, Skarmory will be one Speed point faster at -1 than Snorlax; however, when using Pokemon Online, Skarmory at -1 Speed will tie with Snorlax.
With Drill Peck, Skarmory has an option to deal a good chunk of damage to threats such as Machamp, Exeggutor, and Heracross. Skarmory resists both of Exeggutor's STAB moves, and barring Sleep Powder or Hidden Power Fire, it can switch in with impunity. When going up against Curse Machamp, it is a good idea to boost with Curse first before using Drill Peck in order to prevent Skarmory from losing a good chunk of its health to Cross Chop. Rest is for recovering health and removing paralysis; a paralyzed Skarmory will find it more difficult to check Pokemon it would normally beat, such as Swords Dance Marowak, Curse Machamp, and Belly Drum Snorlax. However, keep in mind that a sleeping Skarmory won't be able to counter threats it normally would, such as setup sweepers and trappers. As a word of warning, opponents can and will capitalize on the two free turns from Rest. It is recommended that you only use Rest when completely necessary; Heal Bell support is also a good idea.Team Options & Additional Comments >>>
Outside of the moves already mentioned, Skarmory has a few options that it can use over Curse. Thief is an interesting possibility because it can remove Leftovers from an opponent, making them more susceptible to being worn down over time. Keep in mind that Thief only works when Skarmory is not carrying an item. Toxic is another option over Curse to drain the opponent's health. However, many Pokemon carry Rest, and Heal Bell support is also fairly common, so Skarmory will often find it difficult to sufficiently wear down many of the tanks that Toxic is meant to counter; however, Toxic is still useful for forcing certain Pokemon to waste a turn Resting. Pokemon that often carry Rest without Sleep Talk, such as Raikou, are especially susceptible to this strategy. Wearing down Electric-types looking to switch in can be very useful, especially with Spikes support. Toxic will also wear down Tyranitar, Rhydon, Cloyster, and Dragonite looking for an easy switch-in, and is effective against defensive Pokemon that don't have Rest and Sleep Talk, such as Starmie and Miltank. Sand-Attack is another option for Skarmory to use against Kangaskhan, and makes a great ploy for annoying opponents in general. The accuracy drops can really ruin opponents, especially those that rely on moves without perfect accuracy, such as Thunder Zapdos and Raikou.
Checks and Counters
Strong special attacks remain the best way to deal with Skarmory, as they hit its much weaker Special Defense. Electric-types such as Zapdos, Raikou, and Jolteon can easily switch into Drill Peck and force Skarmory out with a super effective STAB attack. Mixed sweepers such as Nidoking, Dragonite, Tyranitar, and Fire Blast Snorlax can all come in and do a great deal of damage to Skarmory. Vaporeon is a deadly special sweeper which can scare out Skarmory and use the free turn to boost. While not common, Charizard can come in on Skarmory, threaten it with Fire Blast, and use Belly Drum as it switches out. Cloyster and Forretress can easily set up Spikes on Skarmory. Steelix, Kangaskhan, Rhydon, and Tyranitar are all slower than Skarmory after a Curse boost, allowing them to force Skarmory out with Roar after it uses Whirlwind—in GSC, phazing moves fail if they go before the opponent moves. Houndoom and Tyranitar can rack up Pursuit damage on Skarmory by threatening it with powerful Fire-type moves. Starmie and Suicune can threaten Skarmory with a STAB Surf, and Starmie can even get a free turn to clear away Spikes with Rapid Spin. However, be aware that many of the counters mentioned above will be surprised by the occasional Toxic. Snorlax with Fire Blast can surprise Skarmory with a 2HKO, while Lovely Kiss versions can cripple Skarmory and then proceed to use Belly Drum to rip through the rest of the team.