Mollux is commonly seen taking advantage of its high Special Attack and good offensive STAB move combination by holding a Choice Scarf, allowing it to revenge kill several prominent offensive threats in the metagame. Access to Trick makes it an even better Choice Scarf user, as it can cripple bulky, passive Pokemon that might try to switch into it. Mollux's unique Fire / Poison typing and its access to Dry Skin allow it to check common Fairy- and Water-types quite well. In addition to Mollux's useful typing and ability, its good special bulk, wide support movepool, and access to reliable recovery allow Mollux to support the team in many ways, such as with Rapid Spin, Heal Bell, Stealth Rock, and Toxic Spikes.
One of Mollux's main drawbacks is its middling Speed; without Choice Scarf, Mollux is rather easy to outspeed and force out, as its weaknesses to the common Ground-, Psychic-, and Rock-types are easily exploitable. The 4x weakness to Ground is especially troubling, as Mollux finds itself unable to deal much damage at all to the very common Colossoil and is easily OHKOed by Earthquake. Other attackers such as Keldeo and Azumarill have adapted to its presence and tend to run Ground-type coverage to handle Mollux more easily, which can make it even tougher for Mollux to switch in safely.
Fire Blast is Mollux's strongest reliable STAB move and is its best option for cleaning up late-game. Flamethrower, however, can be used as an alternative if a 100% reliable answer to Cawmodore is needed; a Fire Blast miss can sometimes mean a loss against a +6 Cawmodore. Sludge Wave allows Mollux to deal massive damage to Fairy-type Pokemon such as Azumarill, Mega Gardevoir, and Sylveon. Hidden Power Ground rounds out Mollux's coverage by hitting Heatran and opposing Mollux, which would otherwise wall Mollux's STAB combination, for 4x super effective damage. Thunderbolt can be used instead to hit Water-types such as Keldeo, Mega Gyarados, and Naviathan harder. Trick is in the final slot to cripple common walls that may try to sponge Mollux's attacks, such as Chansey.
The EV spread is straightforward, maximizing Mollux's damage output and Speed. Choice Scarf allows Mollux to act as a revenge killer and outspeed Pokemon such as Cawmodore and Syclant. A Modest nature secures the OHKO on Mega Gardevoir with Sludge Wave while letting Mollux outpace everything up to Syclant; however, a Timid nature can be used to outspeed even faster threats such as Mega Lopunny and Mega Manectric at the cost of some power. Dry Skin gives Mollux an immunity to Water-type moves, potentially giving it some switch in and healing opportunities.
As a Choice Scarf user, Mollux can be brought in as a revenge killer mid-game or to clean up weakened teams late-game. This set is a good fit for both offensive and balanced teams, as it can easily revenge kill and OHKO threats such as Mega Pinsir and Cawmodore with no prior damage, as well as Mega Gardevoir after Stealth Rock damage. While Mollux can easily switch into resisted hits, be wary of Pokemon that commonly carry coverage that Mollux is weak to, specifically Ground-type attacks, such as Mega Altaria's Earthquake, Keldeo's Hidden Power Ground, and Azumarill's Bulldoze. Also, keep in mind that while Mollux's base 76 Speed coupled with Choice Scarf is enough to outspeed most unboosted threats, naturally faster Pokemon that can boost their Speed, such as Mega Charizard X and Aurumoth, will outpace Mollux regardless, so Mollux should not be relied on to revenge kill them.
Mollux has trouble with Ground-types and is often forced out by them. Therefore, its best partners are strong Grass- and Water-types, such as Necturna, Keldeo, and Arghonaut, which can all help break down opposing Ground-types. Fighting-types such as Tomohawk, Keldeo, and Mega Lopunny also pair well with Mollux, as they can take on specially defensive Pokemon that might try to wall Mollux, such as Chansey and Tyranitar. In return, Mollux can cover their weakness to Fairy-type moves. Mollux's typing gives it a weakness to Stealth Rock, so teammates that can remove entry hazards are appreciated. Colossoil makes for an excellent teammate, as it can provide Rapid Spin support, ensuring that Mollux doesn't get worn down too quickly. In return, Mollux resists or is immune to every one of Colossoil's weaknesses. Wish support from a teammate such as Chansey, Sylveon, or Clefable is very much appreciated, as this strengthens Mollux's ability to check opposing threats such as Mega Scizor and Cawmodore if Stealth Rock or Spikes is set up on Mollux's side of the field.
Fire Blast is Mollux's strongest STAB attack, allowing it to demolish opposing Grass-types and Steel-types such as Necturna, Ferrothorn, and Skarmory. Flamethrower is also a reasonable option with perfect accuracy and is the preferred option if Mollux is running Calm Mind. Sludge Wave provides coverage against Fairy-types such as Sylveon, Clefable, and Azumarill. Recover allows Mollux to heal off damage taken from entry hazards and Life Orb recoil. Hidden Power Ground provides important coverage against Heatran and opposing Mollux. Keep in mind that Mollux needs some prior damage on bulkier variants of Heatran to secure the OHKO and fears Heatran's Earth Power. Thunderbolt can be used to hit bulky Water-types harder and allows Mollux to OHKO Keldeo after Stealth Rock damage if holding Life Orb. Thunder is an option here if Mollux has rain support from its teammates. Calm Mind allows Mollux to boost its Special Attack and Special Defense to attempt a sweep. However, it struggles to accomplish much if opposing Ground-types, namely Colossoil, are still present.
Maximum investment in Special Attack and a Modest nature maximize Mollux's offensive potential. 48 EVs in Speed ensure that Mollux outspeeds Adamant Azumarill and defensive Pokemon such as Heatran, Cyclohm, and Necturna. The remaining EVs are put into HP to increase Mollux's bulk. Life Orb is the preferred item, as it maximizes Mollux's damage output and is especially useful if Mollux has Wish support or rain support to keep it healthy throughout the match. Black Sludge, however, is also an option for reliable recovery, and it is the preferred option if running Calm Mind. Air Balloon is also an option that lets Mollux serve as a much safer check to foes that commonly carry Ground-type coverage, notably Dragon Dance Mega Altaria. Dry Skin gives Mollux a useful immunity to Water-type moves. An alternate EV spread of 208 HP / 252 Def / 48 Spe and a Bold nature can be used on Calm Mind sets to bolster Mollux's physical bulk and increase setup opportunities while still hitting the same Speed benchmark.
Bring Mollux in on Water-type moves if at all possible, as this will heal off damage Mollux might have taken earlier from Life Orb recoil or entry hazards. Mollux makes for an excellent check to Fairy-types such as Sylveon, Azumarill, and Clefable, so bring Mollux in to punish the foe with its strong attacks. Be wary of Pokemon that commonly carry Ground-type coverage, such as Heatran, Mega Altaria, and Keldeo, as this can spell doom for Mollux if it is not holding an Air Balloon. If attempting a sweep with Calm Mind, make sure that opposing Ground-types are KOed or heavily worn down first.
Mollux is easily forced out by Ground-types, as it has trouble hitting them for heavy damage, so strong Water- and Grass- types such as Azumarill, Keldeo, and Serperior are its best offensive partners. Mollux is checked by Psychic-types, so Pursuit trappers such as Colossoil and Tyranitar make for good teammates. Mollux, in turn, can cover their weaknesses to Fairy-, Grass-, and Water-type attacks. Rain support from Pokemon such as Politoed and Damp Rock Tomohawk helps Mollux thanks to its Dry Skin, allowing it to heal off damage taken from entry hazards or Life Orb recoil and also use Thunder reliably. U-turn and Volt Switch users such as Colossoil, Talonflame, and Rotom-W can bring Mollux in safely so it can start launching its strong attacks. Gothitelle can trap and remove opposing Chansey, allowing Mollux to more freely use its special attacks without being walled. Pokemon such as Tomohawk, Ferrothorn, and Landorus-T can all help check physical attackers for Mollux and set up Stealth Rock or Spikes. Entry hazard support is especially helpful for wearing down opposing Colossoil; two switches into Stealth Rock or one layer of Spikes ensures that Mollux can 2HKO even Assault Vest Colossoil with a Life Orb-boosted Fire Blast. Stealth Rock with a layer of Spikes puts most variants of Heatran into KO range for Hidden Power Ground.
Lava Plume gets a STAB boost and has perfect accuracy and a decent burn chance, discouraging physical attackers from switching in. Sludge Bomb is used to break down the Fairy-types that Mollux checks so well, such as Sylveon, Clefable, and Azumarill, and it also has a good chance of poisoning the foe. Recover restores Mollux's health and allows it to check special attackers several times throughout a match. The last slot depends on what type of support you'd like Mollux to provide. Rapid Spin allows Mollux to remove entry hazards from your side of the field. Alternatively, Mollux makes for a viable Stealth Rock setter thanks to its bulk. Heal Bell allows Mollux to clear its teammates of status ailments. Toxic Spikes is also an option to help wear down the opposing team.
Mollux can opt to run more than one of the supporting moves listed above on its moveset. However, this means one of its STAB moves or Recover must be dropped. Dropping one of Mollux's STAB moves compromises its ability to check certain Pokemon; if Mollux doesn't run Lava Plume, it becomes bait for Cawmodore, Ferrothorn, and Scizor, and if Mollux doesn't run Sludge Wave, it becomes bait for Pyroak, Cyclohm, and Mega Altaria. Giving up Recover compromises Mollux's longevity and limits the number of times Mollux will be able to come in and support its team, but this is a reasonable option if Mollux has Wish support from its teammates. Hidden Power Ground can also be run in one of the moveslots so that Mollux isn't completely walled by Heatran and opposing Mollux; although this set has trouble finding room for the move, it's a viable option with the proper support.
The EVs and a Calm nature maximize Mollux's great special bulk, allowing Mollux to come in safely on many special attackers and support the team. Black Sludge provides Mollux with passive recovery. Dry Skin provides Mollux with a useful Water immunity and more switch in and healing opportunities.
Bring Mollux in on predicted Water- and Fairy-type moves, as this will allow Mollux time to set up entry hazards, remove them with Rapid Spin, or clear its teammates of status with Heal Bell. Be sure to keep Mollux healthy with Recover; its weakness to Stealth Rock can otherwise leave it worn down quickly and compromise its ability to check special attackers. Generally, Mollux should try to stay away from physical attackers and Psyshock users, which can prey on Mollux's lower physical bulk.
Pokemon that can handle physical hits and Ground-type attacks aimed at Mollux are great teammates. Landorus-T is a great partner because it is immune to Ground-type attacks and can easily take physical hits, while Mollux covers Landorus-T's weaknesses to Water and Ice in return. Tomohawk also makes for a great teammate and can check a plethora of physical attackers that threaten Mollux. Mollux is forced out by Psychic-type Pokemon with Psyshock, such as Latios. A Pursuit trapper such as Colossoil or Tyranitar can prove to be a handy teammate for this reason. Colossoil can also bounce back opposing entry hazards with Rebound, taking considerable pressure off of Mollux. Mollux works well on a rain team, providing the team with a helpful 4x resistance to Grass-type moves, checking Electric-types such as Mega Manectric, Zapdos, and Rotom-W, providing Rapid Spin support, and gaining even more passive recovery with Dry Skin. Therefore, rain setters such as Politoed and Damp Rock Tomohawk make for good teammates. Pokemon that can check Talonflame, such as Cyclohm, Rotom-W, and Tyranitar, can pair well with Mollux, as Mollux is setup bait for bulky variants of Talonflame and takes hefty damage from its Flying-type moves. Wish support from a teammate such as Chansey, Sylveon, or Clefable is helpful, as this keeps Mollux healthy and gives it more opportunities to support the team.
Eruption is a very powerful Fire-type move if Mollux is at full health and is deadly with a Choice Scarf, but it requires entry hazard removal or Wish support to function optimally. Mollux can act as a rain setter with Rain Dance alongside Damp Rock, but Mollux is a bit strapped for moveslots as it is, so rain support is best provided by Mollux's teammates. Toxic can be used to whittle away at the foe's HP, but Mollux's easily exploitable Ground weakness and weakness to physical attackers limit its potential as a Toxic staller. Will-O-Wisp is an option to cripple physical attackers that might switch into Mollux, but Mollux's most common switch-in, Colossoil, can either bounce it back with Rebound or gain an Attack boost with Guts, limiting its effectiveness. Acid Spray is an interesting option that allows Mollux to defeat Chansey one-on-one and can be used on a non-Choice Scarf set.
Checks and Counters
Ground-types and Ground-type Coverage: While they don't appreciate coming in on a strong Fire-type attack, Ground-types such as Colossoil and Landorus-T can easily come in on Mollux's other attacks and threaten it out with their super effective STAB attacks. On top of this, any Pokemon that carries Ground-type coverage, such as Krilowatt, Syclant, or Mega Altaria, can easily threaten to KO Mollux.
Psychic-types: Psychic-types, especially those with access to Psyshock, such as Latias, Latios, and Mega Gardevoir, can all deal heavy damage to or KO Mollux, but they must be wary of switching into Sludge Wave.
Talonflame: Talonflame heavily threatens Mollux with its strong Brave Bird and can deal significant damage to all of Mollux's sets due to Mollux's lower physical bulk. In addition, specially defensive variants of Talonflame can use Mollux as setup bait.
Heatran: The only moves that threaten Heatran are Hidden Power Ground and Trick to an extent. Heatran otherwise walls any support set and Choice-locked sets that are locked into Fire- or Poison-type attacks.
Special Walls: Pokemon that can tank special hits such as Tyranitar and Chansey have no problem sponging hits from Mollux. Tyranitar can even eliminate Mollux's passive recovery with Sand Stream, but it doesn't appreciate the potential burn from Lava Plume. Chansey can sponge anything Mollux dishes out, but it must be wary of Trick and can't do much in return besides Seismic Toss.
Faster Pokemon: Any Pokemon that outspeeds Mollux and can hit it for super effective damage, such as Syclant, Stratagem, or Aurumoth, can revenge kill Mollux, but all of them have trouble switching in.