Rayquaza's Dragon Dance set is a beast feared ever since its release in 2003, and it continues to strike terror in the heart of its opponents. After one Dragon Dance, Rayquaza's Attack skyrockets to 598 while its Speed rests at 475, outpacing every unboosted Pokemon in the metagame bar Deoxys-S. Outrage is Rayquaza's most powerful physical STAB attack, and alongside Earthquake, Rayquaza can hit nearly every single Pokemon in the tier for at least neutral damage. Overheat is used in the last slot to get rid of the Pokemon that would give Dragon Dance Rayquaza trouble otherwise: Ferrothorn, Forretress, and Skarmory.
As Dragon Dance Rayquaza strives to be as fast and as powerful as possible, EVs are maxed out in both Attack and Speed with the remaining 4 EVs invested in Special Attack to give Overheat a little boost. As for alternative EV spreads, 40 HP / 252 Atk / 216 Spe can be used, as it outpaces +1 base 90 Pokemon after a single Dragon Dance.
Because Jolly Rayquaza can't always OHKO Lugia with Outrage, Stone Edge can be used over Earthquake to give it just a little more edge in power. Since Choice Scarf Kyogre, Dialga, Zekrom, and Deoxys-A usually run Modest, Adamant, or Mild, an Adamant nature can be used to increase damage output, though it leaves Rayquaza prone to being revenge killed by positive-natured Choice Scarf users. Also, Rayquaza should always run Extreme Speed while using Adamant or any other Attack-boosting nature to beat Deoxys-A. An Adamant nature also allows Rayquaza to OHKO maximum HP Arceus (89.9% - 105.6%, guaranteed OHKO with SR).
Rayquaza can use Haban Berry over Life Orb. With a Haban Berry, Rayquaza has an easier time getting an extra Dragon Dance on Choice Scarf Palkia, Salamence, and Hydreigon, three of Dragon Dance Rayquaza's common revenge killers. Lum Berry can also be used to avoid status such as Will-O-Wisp or Thunder Wave, which are detrimental to Rayquaza's sweep. While it might seem like an unorthodox option, White Herb can be used with V-create to avoid the aftereffects, making for a devastating attack that is not only boosted by Dragon Dance, but also helps if your opponent runs more than one Steel-type on their team. Be warned, as this only works once. Without White Herb, V-create is bad for Dragon Dance Rayquaza, as it takes away the Speed gained from Dragon Dance, as well as opening up Rayquaza to priority attacks, such as Extreme Killer Arceus's Extreme Speed.
Like most other sweepers, Rayquaza prefers entry hazards to be set up. Stealth Rock is extremely useful, as it grants Rayquaza a chance to OHKO standard Lugia. Forretress and Deoxys-S can set up entry hazards with ease. Forretress deserves a special mention, as it has good synergy with Rayquaza, resisting Dragon- and Ice-type attacks, and can spin away enemy entry hazards. Paralysis support is also advised, as it makes Choice Scarf users such as Palkia unable to revenge kill Rayquaza. Lead Kyogre can fulfill this role well and also acts as a good Palkia lure. Substitute can also be used to beat Choice Scarf Palkia that switch in on Dragon Dance.
Due to its frailty, Rayquaza is prone to revenge killing by Scarf users, such as Zekrom, Reshiram, Kyogre, and especially Pokemon such as Palkia, Salamence, and Hydreigon, all of which can outpace Rayquaza even at +1 Speed. As such, Wobbuffet is an excellent partner to Rayquaza, easily trapping and eliminating Scarf users. Wobbuffet can even use Encore and Safeguard to create an opening for Rayquaza to set up. Although Rayquaza is near unstoppable after a Dragon Dance, certain bulky walls can live an Outrage and KO Rayquaza in return. Defensive Groudon takes 59.4% - 70% from Jolly Life Orb Rayquaza's Outrage and can then use Stone Edge to do 63% - 74.1%, an OHKO factoring in Life Orb recoil and Stealth Rock damage. Bold Lugia with maximum Defense investment will always survive an Outrage even after factoring in Stealth Rock damage, taking 61.3% - 72.1%. Lugia can easily KO Rayquaza with Ice Beam, factoring in Stealth Rock damage. Most Kyogre variants make good teammates with Rayquaza due to their ability to check Support Groudon. Thanks to Air Lock, the rain which Kyogre brings does not gimp Overheat's power.
It should be noted that Outrage is not a move to be used lightly. Even at +1 Attack, most Steel-types such as Arceus-Steel and Ferrothorn can live an Outrage and proceed to cripple it with Will-O-Wisp or Thunder Wave, set up Calm Minds or entry hazards, or just KO a weakened Rayquaza with Judgment and Gyro Ball, respectively. Scizor makes a good teammate with its STAB U-turn and nifty STAB Bullet Punch. Tickle Wobbuffet and Pursuit Scizor can easily eliminate any pesky Lugia, paving the way for Rayquaza to sweep. The infamous Double Dance strategy can be used with Salamence, thanks to Salamence being able to KO or severely weaken most of Rayquaza's checks, and vice versa, allowing for a cleaner sweep.
To demonstrate the power of Dragon Dance Rayquaza, as well as how vital entry hazards are for Rayquaza's sweep, the below calculations will show how much damage Rayquaza does to the best physical walls in Ubers after a single Dragon Dance. All the calculations are assuming a Jolly nature and a Life Orb:
Outrage vs. 252/176+ Lugia: 64.66 - 76.44%
Outrage vs. 252/16 Lugia: 80.28 - 94.71%
Outrage vs. 252/0 Arceus: 82.2 - 96.62%
Outrage vs. 252/252+ Arceus: 61.26 - 72.07%
Outrage vs. 252/252+ Groudon: 59.9 - 70.54%
Outrage vs. 252/0 Dialga: 100.49 - 118.31%
Outrage vs. 252/252+ Kyogre: 81.18 - 95.54%
As you can see with the above calculations, with Stealth Rock and Spikes support, Rayquaza can get past even the bulkiest of Pokemon. As such, it is recommended that Rayquaza is used as a late game sweeper, as after residual damage and entry hazards, Rayquaza will be very difficult to stop.