Gyarados

Life Orb is the recommended item when using a completely offensive EV spread, as it allows Gyarados to OHKO or 2HKO most Pokémon in OU (with the exception of the bulkiest walls like Skarmory and Forretress). Leftovers, however, is viable on alternative EV spreads such as 72 HP / 252 Atk / 184 Spe, designed to outrun positive base 115s, mainly Starmie, after a Dragon Dance. Life Orb combined with residual damage also depletes Gyarados's health fast, whereas Leftovers can provide some healing.

After a Dragon Dance, not many Pokémon can withstand Gyarados's power. However, it is during the set-up process that Gyarados encounters problems. Bulky Water-types that invest in Defense, including Suicune and Vaporeon, can stop Gyarados cold, especially if they wield Hidden Power Electric. Bulky physical walls, such as Skarmory, Forretress, and Dusknoir, can phaze, Explode on, and burn it respectively, ending its sweep. Celebi (should Bounce or Ice Fang be absent), Cresselia, bulky Rotom-A, and Swampert can also be problematic as they can either paralyze it, phaze it, or hit it with an Electric-type attack, while Gyarados fails to 2HKO in return without Dragon Dance boosts. Other Pokémon who can be problematic are Choice Scarf Gengar and Rotom-A, who outpace Gyarados even after one Dragon Dance and possibly even two depending on how much Speed Gyarados runs.

Because offensive Gyarados is typically found on offensive teams, it will often appreciate powerful and hard-hitting partners. Life Orb Starmie can OHKO Skarmory and Forretress, and 2HKO Vaporeon and Suicune, essentially getting rid of four of Gyarados's top counters. Choice Specs Rotom-A performs similarly, and can use Shadow Ball to scare Cresselia and Celebi away. Having Scizor in your party makes Choice Scarf Rotom-A and Gengar think twice before switching in due to Pursuit. The same applies to Tyranitar, who causes the aforementioned three problems, Dusknoir, Cresselia, and even some Celebi. Life Orb Gengar is also a stellar Gyarados partner, OHKOing Rotom-A with Shadow Ball, while denting Cresselia, Celebi, and Dusknoir in the process.

The EVs balance between offense and defense. 156 HP EVs lets Gyarados survive two Life Orb Heatran's Fire Blasts after Stealth Rock. 96 Defense EVs allows Gyarados to avoid a 2HKO by Quick Attack by Choice Band Scizor. 184 EVs in Speed means Gyarados will outspeed Choice Scarf Tyranitar and +Speed base 115s after a Dragon Dance. The rest are put into Attack. There are some alternate EV spreads to consider for different reasons, however. 152 HP / 176 Atk / 36 Def / 144 Spe gives Gyarados the power to OHKO Zapdos with Stone Edge, while still being able to handle Lucario when needed. 152 HP / 168 Def / 188 Spe sacrifices power for the ability to better handle the likes of Heracross and still take down frail foes like Gengar.

This set will work significantly better by packing an anti-Stealth Rock lead on your team. Choice Scarf Jirachi is fairly reliable at stopping Aerodactyl, Azelf, and Mamoswine leads, making it a great partner for Bulky Gyarados. Gyarados also resists all of Jirachi's weaknesses. Other leads, such as Taunt / Stealth Rock Aerodactyl or Azelf, can accomplish the same task while supporting Gyarados with Stealth Rock. Aerodactyl's higher Speed can come in use though due to Azelf being the most common lead. A Rapid Spinner, such as Forretress or Starmie, can be useful, though most Rapid Spinners share the common counter of Rotom-A with Gyarados.

Bulky Gyarados is a great lure for Electric- and Rock-type attacks, as well as bulky status-inducing counters. Gyarados can beat the latter with Taunt, but not the former, so packing Pokémon who can set up on Rock- and Electric-type attacks is recommended. Ground-type attackers like Flygon and Dugtrio are ideal as they resist both; while Gliscor may not resist Rock-type attacks, it has the Defense to take those hits well. Electric-type attacks can often be set up on by Jolteon or Electivire (the latter forming the infamous "GyaraVire" combo), and Rock-type attacks by Lucario or Metagross.

248 HP EVs caps Gyarados's HP off at 393, allowing it to switch into Stealth Rock five times. Defense is maximized and the remaining EVs are placed in Special Defense. Another possible EV spread is 252 HP / 80 Def / 176 SpD with a Careful nature, which lets Gyarados have an easier time against special attackers like Heatran and still do well against Infernape, Lucario, and Scizor thanks to Intimidate.

This set has a lot of problems with Taunt users who either resist Waterfall or have the defenses to take it. Opposing Gyarados with Taunt can set up freely, while Taunt Skarmory can set up multiple layers of Spikes. While this set is great at shuffling the opponent's team, it cannot do that against strong special attackers with Thunderbolt, such as Jolteon, Magnezone, Rotom-A, Zapdos, and Gengar. When not using Roar, a major problem this set faces is the lack of type coverage, while still being unable to shuffle the opponents' team. Choosing a moveset of Rest + Sleep Talk + Dragon Dance + Waterfall can be deadly, but is walled to death by Suicune, Vaporeon, and Celebi. All three can retaliate against Gyarados in some way. Choosing a moveset of Rest + Sleep Talk + Waterfall + Stone Edge solves this problem, but Gyarados often finds its attacks doing little-to-average damage. Pokémon like Suicune and Breloom can take advantage of Gyarados's weak attacks and set up on it via Calm Mind or Substitute. Waterfall + Avalanche is even worse; in this case, foes like Empoleon and Cresselia, in addition to the aforementioned Suicune, will gladly come in on Gyarados and set up right in its face.

To help Gyarados out, Blissey can stall out Suicune, Vaporeon, Cresselia, Empoleon, and even Celebi. In return, Gyarados fends off the Fighting-types that endanger Blissey's life. Rotom-A can check some of Gyarados's counters well, including Dusknoir and Celebi. Entry hazard support is very helpful, as Roar racks up residual damage. Toxic Spikes support can help it stall out bulky Water-types that lack an Electric-type move; an essential partner to set Toxic Spikes up is Roserade, but Forretress can also set them up reliably. Forretress and Skarmory are the best options for setting up Spikes, especially since this Gyarados is commonly used on stall teams. They both have the Defense to set up Spikes on physically offensive Pokémon. There are many Pokémon who can set up Stealth Rock to aid Gyarados, such as Blissey, Forretress, Hippowdon, Skarmory, and Swampert. Just use whichever fits your team best and remember not to overload Pokémon with entry hazards, as they may not always be able to get all of them up. Specially-based Pokémon in general are useful teammates for Gyarados.

Other options for this set include Aqua Tail for use over Waterfall as the lack of Speed can justify the use of a more powerful, albeit less accurate move. Bounce can also be used as it hits Breloom and Celebi, for example, harder than any other move, although the two turns it takes to hit has its downsides as it's vulnerable to Protect stalling and also must watch out for slower Pokémon who either resist Bounce or have the Defense to take it, such as some Rotom-A, switching in as it Bounces up and then taking it out the next turn. 184 Speed EVs put Gyarados at 244 Speed, just ahead of Jolly Tyranitar, but adding a few EVs to ensure Gyarados is faster than defensive Celebi can be a good idea. Running maximum Speed to Speed tie with opposing neutral natured Gyarados is also perfectly acceptable.

Here are some damage calculations to show just how powerful Choice Band Gyarados is:

• Waterfall vs. 4 HP neutral nature Rotom-A: 81.8% - 96.7%
• Waterfall vs. 252 HP / 120 Def +Defense nature Rotom-A: 52.6% - 62.5%
• Waterfall vs. 252 HP / 252 Def +Defense nature Rotom-A: 47.4% - 56.3%
• Waterfall vs. 248 HP / 228 Def +Defense nature Zapdos: 44.6% - 52.7%
• Aqua Tail vs. 4 HP neutral nature Rotom-A: 91.7% - 100%
• Aqua Tail vs. 252 HP / 120 Def +Defense nature Rotom-A: 59.2% - 70.1%
• Aqua Tail vs. 252 HP / 252 Def +Defense nature Rotom-A: 53.3% - 63.2%
• Aqua Tail vs. 248 HP / 228 Def +Defense nature Zapdos: 50.4% - 59.5%
• Payback vs. 4 HP neutral nature Rotom-A switching in: 100%
• Payback vs. 252 HP / 120 Def +Defense nature Rotom-A switching in: 88.2% - 100%
• Payback vs. 252 HP / 252 Def +Defense nature Rotom-A switching in: 78.9% - 93.4%
• Payback vs. 252 HP / 220 Def +Defense nature Celebi switching in: 63.9% - 75.2%
• Payback vs. 136 HP / 156 Def neutral nature Starmie switching in: 100%
• Stone Edge vs. 248 HP / 228 Def +Defense nature Zapdos: 74.2% - 87.7%
• Ice Fang vs. 252 HP / 220 Def +Defense nature Celebi: 41.6% - 49%
• Bounce vs. 252 HP / 220 Def +Defense nature Celebi: 81.7% - 96.5%

The removal or weakening of Rotom-A, which this set provides by luring it in and then smacking it with Payback, can facilitate a sweep for a number of Pokémon including Lucario, Swords Dance Scizor (who fears Will-O-Wisp), Agility Metagross, and Jirachi. These Pokémon therefore make ideal partners for Choice Band Gyarados. Pokémon like Infernape appreciate the removal of Starmie.

While this set is very powerful, there are still some Pokémon who can cause it problems. Bulky Water-types, such as Suicune and Vaporeon, can take two hits from Stone Edge or Earthquake and hit back with Hidden Power Electric. Therefore, having someone on your team to deal with them is very useful. Celebi makes a great partner to Gyarados for this exact reason as it has high Special Defense to take hits from bulky Water-types and can hit back with STAB Grass-type attacks. Jolteon can make a solid partner as Gyarados lures in Electric-type attacks for it to recover health and it can also scare off bulky Water-types with STAB Electric-type attacks. Cresselia has high Defense to take hits from Gyarados and has Charge Beam to hurt it, so it can be troublesome. Tyranitar and Scizor can therefore make a great partner to this set as they can both easily take hits from Cresselia, hit back with super effective STAB attacks, or even Pursuit should Cresselia try to switch out. Choice Specs Rotom-A also makes an effective partner to Choice Band Gyarados as Thunderbolt deals with bulky Water-types that trouble Choice Band Gyarados while Shadow Ball deals with Cresselia.

While it may be tempting to start using Dragon Dance right away, like you would with any offensive Gyarados set, it's important to keep in mind that this Gyarados is primarily a wall and should be kept in good condition. Unlike the more conventional offensive sets, this Gyarados will virtually never be able to smash through your opponent's team early on in a battle. Gyarados is more of a "win condition"—you can depend on it to finish up in the endgame, but only if you've gotten rid of any potential threats. This primarily refers to wielders of Electricity, but also includes fast, powerful Rock-type attackers like ScarfTar and Life Orb Aerodactyl. You will definitely want at least one solid switch-in for threats like Jolteon and Zapdos. A Jolteon of your own will love to switch into Thunderbolts, and will serve Gyarados very well by shooing away Skarmory and Vaporeon. Swampert is also immune to Electric and carries a bonus Rock resistance, making it a natural choice for a partner. Shaymin is an adorable alternative; she resists Electric, and with Gyarados around, needs not worry about Heatran or Blissey when firing off her powerful Seed Flare.

Uniquely, Toxic Spikes are very helpful to this Gyarados, since opponents like Celebi will be constantly forced to heal away damage instead of spamming Grass Knot for critical hits. A single layer is great, but with two layers, Gyarados will boast assured victory against the likes of Vaporeon, Suicune, and Celebi. Removing Stealth Rock will make it considerably easier to bring Gyarados in and out, so either a fast Taunt lead or a Rapid Spin user is a good idea. Tentacruel and Forretress can both lay down Toxic Spikes and use Rapid Spin, but their synergy with Gyarados is suspect as they pose little offensive threat (and Tentacruel shares an Electric weakness). An offensive Starmie with Rapid Spin is more suitable, despite the shared weakness, because it can lure in Rotom-A and take it down with a manly Hydro Pump. Overall, remember that this Gyarados is more of a supporter than a supportee; it's probably not a Pokemon to build your team around.

Theoretically, one could put an offensive twist on this set by investing heavily in Speed and possibly Attack in order to threaten opponents earlier, while maintaining some longevity and a virtual immunity to status. After a Dragon Dance, 88 Speed outruns Jolly Jirachi and Timid Zapdos, which should be the minimum for any offensive RestTalk Gyarados. Below that, you could aim to beat Jolly Lucario and Timid Roserade, but the feral flower is nearly always used in the lead slot and Lucario will simply ExtremeSpeed anyway. Gliscor, although somewhat annoying with Taunt, will never switch into any Gyarados. 184 Speed will outspeed Starmie, although whether you'll be able to KO it with Waterfall is another matter. The problem with any fast, powerful RestTalk Gyarados is that it won't be able to wall and set-up against many of the same opponents, such as Celebi, who will beat it without Special Defense investment. Feel free to experiment, but this spread is tried and true, like a delicious lemon meringue pie.