Surprised this set isn't up yet, as it's IMO Gyarados's best set and is far more effective than either Bulky or Offensive Dragon Dance.
It doesn't even have an OO mention :/
Anyways...
Gyarados
[SET]
name: Substitute + Dragon Dance
move 1: Substitute
move 2: Dragon Dance
move 3: Waterfall
move 4: Bounce / Stone Edge
item: Leftovers
nature: Adamant
evs: 80 HP / 224 Atk / 20 Def / 184 Spe
[SET COMMENTS]
<p>Apart from RestTalk, all of Gyarados's sets loathe status. This set aims to avoid crippling status through the use of Substitute. By using Substitute, Gyarados is able to safely set up on moves such as Scald, Toxic, Thunder Wave, Will-O-Wisp, and other status moves that would otherwise drastically decrease its likelihood of sweeping. Substitute also prevents Gyarados from being revenge killed by Choice Scarf users such as the omnipresent Rotom-W, taking the incoming Volt Switch or Thunderbolt and allowing Gyarados to either attack or set up with Dragon Dance. With its excellent bulk, typing, and abilities, Gyarados can easily grab a Dragon Dance boost and plow through the opposing team. Waterfall is the obligatory STAB move, hitting many Pokemon for neutral damage, and benefiting from the power boost that provided by Drizzle. Bounce and Stone Edge are both viable options for the last slot; Bounce allows Gyarados to dispatch of bulky Grass-types such as Celebi, while Stone Edge offers superior coverage against Dragon- / Flying-types such as Dragonite and Salamence as well as hitting Rotom-W for neutral damage. The EVs for this set allow Gyarados to outspeed all base 115 Speed Pokemon, such as Starmie, after one Dragon Dance, and also prevents a burned Ferrothorn from breaking its Substitutes with Power Whip. However, it is important to note that even an Intimidated Scizor is still able to break Gyarados's Substitutes with U-turn at least some of the time.</p>
[ADDITIONAL COMMENTS]
<p>Both of Gyarados's abilities are viable for this set. Intimidate makes it much easier for Gyarados to set up on physical attackers, and also allows Gyarados to support the team, should it not find an opportunity to set up. Moxie allows Gyarados to take advantage of Pokemon sacrificed to break its Substitutes, as Gyarados's Attack increases with each KO. Because this set can be phazed by Skarmory and bulky Water-types, said Pokemon must be eliminated before attempting a sweep. Rotom-W pairs excellently with Gyarados; it threatens Skarmory and Water-types with its STAB Electric-type moves, and spreads burn throughout the opposing team with Will-O-Wisp. In general, burn support is greatly beneficial, especially to Intimidate variants of this set; burned, physically oriented Pokemon, such as Ferrothorn and Jirachi, will no longer be able to break Gyarados's Substitutes, allowing Gyarados to safely set up and wreak havoc. Rapid Spin support is also greatly appreciated, as this set drains HP quickly with Substitute and is consequently much more vulnerable to Stealth Rock. Entry hazards of your own, as well as Rain support, can help Gyarados net more KOs. Ferrothorn synergizes well with Gyarados, as it resists the Rock- and Electric-type moves that Gyarados is weak to, and has access to Stealth Rock and Spikes. Ferrothorn also fits well on most Rain teams.</p>
It doesn't even have an OO mention :/
Anyways...
Gyarados
[SET]
name: Substitute + Dragon Dance
move 1: Substitute
move 2: Dragon Dance
move 3: Waterfall
move 4: Bounce / Stone Edge
item: Leftovers
nature: Adamant
evs: 80 HP / 224 Atk / 20 Def / 184 Spe
[SET COMMENTS]
<p>Apart from RestTalk, all of Gyarados's sets loathe status. This set aims to avoid crippling status through the use of Substitute. By using Substitute, Gyarados is able to safely set up on moves such as Scald, Toxic, Thunder Wave, Will-O-Wisp, and other status moves that would otherwise drastically decrease its likelihood of sweeping. Substitute also prevents Gyarados from being revenge killed by Choice Scarf users such as the omnipresent Rotom-W, taking the incoming Volt Switch or Thunderbolt and allowing Gyarados to either attack or set up with Dragon Dance. With its excellent bulk, typing, and abilities, Gyarados can easily grab a Dragon Dance boost and plow through the opposing team. Waterfall is the obligatory STAB move, hitting many Pokemon for neutral damage, and benefiting from the power boost that provided by Drizzle. Bounce and Stone Edge are both viable options for the last slot; Bounce allows Gyarados to dispatch of bulky Grass-types such as Celebi, while Stone Edge offers superior coverage against Dragon- / Flying-types such as Dragonite and Salamence as well as hitting Rotom-W for neutral damage. The EVs for this set allow Gyarados to outspeed all base 115 Speed Pokemon, such as Starmie, after one Dragon Dance, and also prevents a burned Ferrothorn from breaking its Substitutes with Power Whip. However, it is important to note that even an Intimidated Scizor is still able to break Gyarados's Substitutes with U-turn at least some of the time.</p>
[ADDITIONAL COMMENTS]
<p>Both of Gyarados's abilities are viable for this set. Intimidate makes it much easier for Gyarados to set up on physical attackers, and also allows Gyarados to support the team, should it not find an opportunity to set up. Moxie allows Gyarados to take advantage of Pokemon sacrificed to break its Substitutes, as Gyarados's Attack increases with each KO. Because this set can be phazed by Skarmory and bulky Water-types, said Pokemon must be eliminated before attempting a sweep. Rotom-W pairs excellently with Gyarados; it threatens Skarmory and Water-types with its STAB Electric-type moves, and spreads burn throughout the opposing team with Will-O-Wisp. In general, burn support is greatly beneficial, especially to Intimidate variants of this set; burned, physically oriented Pokemon, such as Ferrothorn and Jirachi, will no longer be able to break Gyarados's Substitutes, allowing Gyarados to safely set up and wreak havoc. Rapid Spin support is also greatly appreciated, as this set drains HP quickly with Substitute and is consequently much more vulnerable to Stealth Rock. Entry hazards of your own, as well as Rain support, can help Gyarados net more KOs. Ferrothorn synergizes well with Gyarados, as it resists the Rock- and Electric-type moves that Gyarados is weak to, and has access to Stealth Rock and Spikes. Ferrothorn also fits well on most Rain teams.</p>