In the transition into the 5th generation, all the stars aligned for Jynx to make her relevant in OU. In addition to the advent of Drizzle Politoed, Jynx received Dry Skin as her Dream World ability, which grants her an immunity to Water-type attacks, making her an excellent addition to rain or hail teams. Jynx also boasts an above average Special Attack, decent Special Defense, and enough Speed to outspeed most of OU's neutral-natured Dragon-types. This, combined with Jynx's diverse movepool, highlighted by a somewhat reliable sleep-inducing move in Lovely Kiss, makes her very difficult to take down when used correctly. However, Jynx still has the same problems that she had in the past. Jynx suffers from weaknesses to Stealth Rock and Pursuit, while her abysmal Defense means any strong physical attack will either cripple or outright KO her. While the shift to BW brought Jynx some great tools to work with, it also brought new threats such as Terrakion and Ninetales, which turns Dry Skin into a liability. Despite all of this, Jynx can prove to be a formidable sweeper given the right support.
With Nasty Plot, Jynx can boost her already excellent Special Attack to frightening levels, and at +2 her STAB Ice Beam will sting even foes that resist it. Lovely Kiss is the main selling point of this set, as the new mechanics in BW can enable Jynx to essentially disable one of your opponent's Pokemon with a decent 75% accurate move and proceed to set up Nasty Plots. Unlike sun teams, which can utilize various abusers with Sleep Powder, rain and hail teams don't have access to many reliable sleep inducers barring Breloom. Jynx fills the role of putting rain or hail counters to sleep while also abusing weather much more effectively than Breloom. Substitute works great in tandem with the recovery Jynx receives from Dry Skin, allowing her to make 12 Substitutes from full HP, factoring in Leftovers. These Substitutes can be used to stall out Sucker Punches from Pokemon such as Toxicroak or moves with low PP and/or accuracy such as Ferrothorn's Gyro Ball. Substitute also provides vital protection from prominent threats such as Scizor and Terrakion who will attempt to exploit Jynx's abysmal Defense and average Speed.
Jynx is an excellent answer to rain stall teams as she can set up on standard components of them. Bulky Water-types such as Politoed, Tentacruel, Vaporeon, Gastrodon, and Jellicent can't attempt to burn Jynx with Scald as Dry Skin grants her an immunity to Water-type attacks. Furthermore, bulky Water-types typically carry Ice Beam as secondary coverage, which Jynx resists. In addition, Jynx outspeeds all of the aforementioned Water-types and can use Substitute to block any attempted status. Blissey, one of the most prominent special walls in OU, can only 5HKO Jynx with Seismic Toss, which is more than enough time for Jynx to get to +6 and 2HKO Blissey with Ice Beam. The few rain stall Pokemon that Jynx can't handle, such as Jirachi, can be simply put to sleep with Lovely Kiss.Team Options & Additional Comments >>>
Jynx can use a Substitute + Calm Mind set, but the power drop is noticeable and Jynx doesn't have the bulk or Speed to pull it off in OU. Jynx can also opt to use a Mean Look + Perish Song set to trap and eliminate walls, but as previously mentioned, she is just too frail. Jynx can run a dual screen set, but she doesn't have the bulk, Speed, or secondary utility to compete with the likes of Azelf and Espeon. Toxic can be used in tandem with Dry Skin, Leftovers, and Substitute to stall out the opponent in rain or hail, but this type of set would run into problems with Steel-types and faster opponents. Psyshock is an option for a secondary STAB, as is Psychic, to hit special walls and Bulk Up Fighting-types such as Breloom and Conkeldurr harder. Psychic-type attacks can also deal with Fighting-types that often threaten hail teams, but it provides poor coverage alongside Ice Beam and Jynx is better off using Focus Blast to deal with Steel-types. Grass Knot or Energy Ball can be used to quickly KO the Water-types that Jynx walls, but Jynx is generally better off using Water-types to set up as opposed to killing them off right away. Taunt can be used, but it doesn't really do much for Jynx with Substitute in the moveset. Shadow Ball can be used, but Ice Beam covers more threats with more power. Finally, Sweet Kiss can be used to annoy an opponent while behind a Substitute, but is an unreliable option.
Checks and Counters
Before even thinking about trying to wall Jynx, you'll need to take Lovely Kiss into account as it can enable her to get past usual counters. For instance, specially defensive Jirachi can usually stop Jynx as it resists Ice Beam and can break Jynx's Substitutes with Iron Head. However, if Jirachi happens to switch into a Lovely Kiss, Jynx can proceed to boost to +6, at which point she'll be able to 2HKO Jirachi with Ice Beam. To avoid situations like this, the player should look to sacrifice their most dispensable Pokemon to Lovely Kiss, to preserve their planned counter for Jynx.
Heatran and specially defensive Jirachi are your best bets when looking to stop Jynx. Heatran 4x resists Ice Beam and can KO Jynx even in the rain because Dry Skin's secondary effect essentially cancels out rain's suppression of Fire-type attacks. Specially defensive Jirachi can also take Ice Beams and heal off any damage with Wish. Furthermore, Jirachi gives Jynx no time to set up due to a super effective Iron Head. Jynx struggles in sand and especially sun, as the latter will gradually decrease Jynx's HP each turn thanks to Dry Skin's secondary effect. Furthermore, Ninetales can switch into Jynx and threaten her with sun-boosted Fire-type attacks. Tyranitar changes Jynx's beneficial weather as well, and can take Ice Beams thanks to the Special Defense boost it receives from sand. Tyranitar can also threaten Jynx with either of its super effective STAB moves, though it has to watch out for a +2 Focus Blast. Blissey may look like a full stop to Jynx with its immense special bulk and Natural Cure; however, Jynx outspeeds Blissey so all it can do is attack. Unfortunately, Seismic Toss only manages to 5HKO Jynx while its Ice Beam won't even break through Jynx's Substitutes. Therefore, Blissey can only defeat Jynx if she's using Flamethrower.
Fast physical attackers such as Mienshao and Terrakion can outspeed and KO Jynx due to her poor Defense stat; however, none can take a hit from Jynx when either switching in or attempting to break her Substitute. A good way to go about stopping Jynx with an offensive team is getting a Pokemon that resists Ice Beam to break her Substitute while you switch to a check. For instance, you could break Jynx's Substitute with Scizor's or Rotom-W's U-turn or Volt Switch while they take the Ice Beam, then switch to Terrakion to KO her. Cloyster 4x resists Jynx's Ice-type STAB while being able to break through Jynx's Substitute and KO her with a super effective Rock Blast. However, Cloyster has to be careful switching in, as it has poor Special Defense, so any of Jynx's neutral special attacks will deal heavy damage to it. Scizor resists both of Jynx's STAB attacks and can opt to Pursuit trap or gain momentum off Jynx by breaking its Substitute with U-turn. Despite being weak to her Ice-type attacks, Choice Scarf Haxorus can can check Jynx as it can break through Jynx's Substitute and KO her with a STAB Dual Chop.