We go from the least-used to the most-used member of the Muskedeer squad that is available. Terrakion is quite simply a monster. It has a huge base 129 Attack stat, just a bit lower than that of Garchomp, Mamoswine, and Scizor. Like its fellow Muskedeers, it boasts a blazing base 108 Speed. Its 91/90/90 defenses mean it can take a few hits before going down. Finally, it has one of the best, if not THE best, STAB combination in the game, which helps make up for a relatively small movepool. The combination of Rock and Fighting inflicts supereffective damage on eight of the seventeen Pokemon types, and only a choice few Pokemon resist it. Defensively, it gives Terrakion several useful resistances (including a Stealth Rock resistance) as well as the 50% Sp. Defense boost in a Sandstorm. All this adds up to make Terrakion an extremely threatening Pokemon. Everyone playing in the OU and Uber tiers should be on the lookout for it.
Recommended tiers: OU-Uber
Justified is Terrakion's only ability, but it is extremely powerful when used properly. Every time Terrakion is hit with a Dark-type attack, its Attack stat raises one level. This abilty has great synergy with Beat Up and Terrakion's already huge Attack stat, which is why Whimsicott and Terrakion are popular together on Doubles and Triples teams.
Close Combat and Stone Edge are where it's at with Terrakion. Just these two moves can deal massive amounts of damage to almost any Pokemon. If you don't like CC's Defense drops or SE's shaky accuracy, you can opt for the weaker Sacred Sword and Rock Slide instead. X-Scissor deals serious damage to Psychic types like Cresselia. Earthquake is usually a great move for a physical attacker, but Terrakion's STABs are almost always better. Terrakion can actually make mild use out of Quick Attack, especially on a Choice Band set, since there are Pokemon like Latios and Starmie that outrun it. Terrakion can also make fantastic use out of both Swords Dance and Rock Polish, and is a rarity in that it can viably run both moves on the same set.
Double and Triple options: The Whimsicott/Terrakion combo is fearsome to behold. Whimsicott simply uses Beat Up on Terrakion, who proceeds to wreak the opponent's team with crazy-powerful Justified-boosted attacks. This combo has but a few counters, namely priority abusers and Trick Room. Be on the watch for it whenever you play Doubles or Triples.
Countering Terrakion: It is INSANELY difficult to counter Terrakion. Very few Pokemon resist its STAB combo, and most of those that do exist in the lower tiers. Toxicroak, Nidoqueen, Nidoking, and Golurk are the primary examples. Once you figure out what Terrakion's running, it becomes a bit easier. The Banded set can be revenge killed. The Scarf set's hits are easier to take, meaning you can send in a physical wall like Skarmory. All Terrakion loathe to be burned, so Will-O-Wisp or Scald are fantastic ideas. Unaware Quagsire walls Sword Dancing Terrakion all day, especially if he carries Curse or Scald. Priority is a good idea, as Terrakion is weak to many priority moves. Scizor and Metagross' Bullet Punch, Azumarill's Aqua Jet, Infernape's Mach Punch, and Toxicroak's Vacuum Wave are just a few examples.
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