I've heard they're short of room in hell
Gengar returns for another bout in OU, undisputed as the only Pokemon to consistently remain in the tier over the past decade or so. Gengar has always just been that good, and in XY it is no exception. The XY generation shift does little but benefit Gengar; the new Fairy-type gives Gengar another area to excel in, and the Steel-type losing its Ghost-type resistance makes it easier to Gengar to fit moves into a set, and harder to switch into. Not all is good for Gengar though, the general power creep in the metagame, like new priority abusers, former Ubers, Assault Vest users, and powerful Mega evolutions leave Gengar struggling to keep up. However, Gengar still remains as useful and unique as days past, its typing, ability, and support movepool let it act as a powerful stallbreaker, while its offensive stats and very good Speed-tier don't let it down as an attacker against offensive teams. A number of other traits, such as acting as a Spinblocker, and being an effective Destiny Bond user make Gengar a rather consistent choice for many teams, and quite unpredictable too. If you want to use Gengar, understand its role, its strengths, and its weaknesses. Do that, and you will find it very effective.
name: Utility Attacker
move 1: Substitute
move 2: Shadow Ball
move 3: Will-O-Wisp
move 4: Taunt / Sludge Wave / Disable
item: Black Sludge
evs: 28 HP / 148 SAtk / 80 SDef / 252 Spd
Substitute allows Gengar to play around its poor bulk using its typing's defensive attributes advantageously by forcing the opponent to attack to deal with Gengar, this results in many free substitutes on Pokemon such as Chansey, Clefable, Gliscor, Venusaur, Ferrothorn and Amoonguss. Substitute is also necessary for Disable to function at all, and even against Pokemon that can defeat Gengar with attacks Substitute can block status moves, giving Gengar free turns. Substitute also provides counterplay to Sucker Punch users for Gengar. Shadow Ball is Gengar's STAB of choice, its autonomous neutral coverage is unrivaled, and it does pretty solid damage to most Pokemon, letting Gengar keep the pressure on. Will-O-Wisp is a fantastic move in general, on Gengar it is very valuable for pressuring defensive Pokemon, as well as severely crippling typical checks and counters, especially Pursuit, Shadow Sneak and Sucker Punch users. Will-O-Wisp is almost always a great way to take advantage of a free turn and improves Gengars proficiency against offensive teams. Taunt's ability to stop the opponent from phazing out Gengar's substitutes, healing, setting entry hazards or using Defog turn Gengar is a powerful stallbreaker. Against Pokemon Gengar cant really damage that much while behind a sub such as Chansey, Sylveon, specially defnesive Hippowdon, specially defensive Heatran and other extra resilient special walls Taunt disrupts these Pokemon and makes them easy to switch into, or completely beatable for Gengar. Sludge Wave forms reasonably good coverage with Shadow Ball, and gives Gengar a nice power boost against neutral targets, as well as acting as a potent Fairy-type slayer. Disable disallows the opposing Pokemon from using the move they last used for 3 turns. This allows Gengar to prey upon opposing pokemon that rely on just one move to do significant damage to Gengar, as well as completely shutting down slower choiced attackers. Dropping Will-o-Wisp decreases Gengar's effectiveness against offensive teams however Taunt and Disable in Tandem are a nightmare to stall preventing the opponent from healing, or clearing hazards while Disable renders the opponent unable to damage Gengar at all with mono attack sets many stall Pokemon feature. Focus Blast forms perfect neutral coverage alongside Shadow Ball and is a very useful tool that lets Gengar patch up a weakness to Dark-types that attempt to beat Gengar with Sucker Punch, Pursuit, or just by virtue of their typing in general. It can be used in the last moveslot. Though Tyranitar and Bisharp are easily burned with WoW deterring them, it does not prevent Gengar from getting KO'd in the process. If your team values Gengar to the point where sacking it is unacceptable Focus Blast should be used.
Black Sludge goes excellently with a set that ought to be creating a fair amount of free turns, it is necessary for Substitute to be as effective as possible. 28 HP / 148 SAtk / 80 SDef / 252 Spe Timid lets Gengar' substitutes survive a min SpA Mega Venusaur Giga Drain or Clefable Moonblast which lets Gengar deal with these common threats much more easily. If this is not a massive concern a simple Max SpA / Max Spe spread improves offensive capability while still being very proficient against defense.
Gengar's unpredictability means that a number of moves such as Will-o-Wisp and Taunt will often be a surprise. This lets Gengar act as a solid Taunt lead, even Magic Coat users will falter. If you see opposing Smeargle or Deoxys-D, leading with Gengar is recommended. Against Stall teams Gengar is quite effective as it easily makes free substitutes on stall staples Chansey, Hippowdon, Clefable, and Gliscor. This success is exponentially greater with friendly entry hazards, as it often forces the opponent to switch around. Against stall teams aggressive Stealth Rock use, and getting Gengar into the fray is recommended. Against more offensive Gengar isn't as great, however its Speed can still be useful, Ghost-type weak Pokemon slower than Gengar can be easily checked, so keep that in mind, and Gengar' fast Will-o-Wisp can be used to shut down slower attackers if necessary. Subsitute + Disable preys well upon opponents that have little to hit Gengar with outside one coverage move, scouting for sets with teammates, or excessive substitute use may be helpful. Disable prevents slower choiced attackers from doing anything at all, again, scouting for these is valuable as it can buy Gengar free turns. Ferrothorn is easy prey, for substitute disable as it relies on just one attacking move to beat Gengar. If given a free turn behind a Substitute against a full strength Aegislash it is generally advisable to burn it, although Shadow Ball deals a lot of damage to Aegislash, Gengar will be forced out due to the threat of Shadow Sneak the next turn, therefore Will-O-Wisp will let you do more damage one on one, or make Aegislash much easier to deal with later in the match.
When not using Focus Blast a strong Fighting- or Fairy- type partner to beat up on Dark-types that make life a pain for Gengar is appreciated. Azumarill, Terrakion and Keldeo are in general good choices for this. Gengar switches in to immunities the best, very strong and threatening pokemon that put sufficient pressure on the opponent to elect Fighting, Normal or Ground moves despite Gengar's prescence go well with Gengar. Life Orb Terrakion, for example. Due to the fact that Gengar can effectively render opponents unable to damage it with Disable or Taunt and Substitute, it often forces the opponent to switch. As such, entry hazard stacking racks up damage very efficiently. A skilled entry hazard setting partner, such as Deoxys, Terrakion, Garchomp, or Landorus can really punch holes in team indirectly. As damage from hazards surmount opponents may attempt to remove thse hazards. Opponents may not spin on Gengar to remove hazards thanks to Ghost typing, however they may Defog if Gengar lacks Taunt. Bisharp is a solid partner to Gengar in this regard as thanks to defiant it can acquire a +2 boost if the opponent defogs and you swap in Bisharp, or it can pressure the opponent to just not defogging at all, both favourable outcomes. On top of this Bisharp is a solid answer to answer to the ever present Aegislash who can check Gengar by threatening with its Shadow Sneak. Especially with Taunt this set is very good at stall breaking, insert it on teams that may struggle against this archetype. The few viable stall mons that can actually defeat Gengar such as Specially Defensive Heatran and Knock Off Gliscor need to be dealt with by teammates. Hidden Power Ice Terrakion is a very good Gliscor lure. Pokemon that relatively reliably take advantage of Heatran such as Mega Charizard X are also useful to help keep Heatran worn down.
Bond, Destiny Bond
name: Bond, Destiny Bond
move 1: Destiny Bond
move 2: Shadow Ball
move 3: Sludge Wave
move 4: Focus Blast / Thunderbolt
item: Life Orb
evs: 4 HP / 252 SpA / 252 Spe
Destiny Bond lets Gengar take on a role of an all out attacker scoring KOs with pure power then taking a defensive check it can not muscle past with it. Destiny Bond provides insurance against Sucker Punch users as per turn order, Gengar will move after their Sucker Punch, it will fail, and next turn they will be trapped in a Destiny Bond next turn ensuring at least a trade of pokemon. Shadow Ball is a choice STAB, it has mediocre base power, however the amount of types it hits neutrally is fantastic, as well as the resistances to it uncommon. Focus Blast is important coverage for Normal and Dark types such as Tyranitar that resist Shadow Ball. Sludge Wave despite poor neutral coverage has the most power of any of Gengar's STAB, and thus it does the most raw damage to a neutral target and it has the utility of getting rid of Fairy-types. Thunderbolt deserves recognition as being capable of 2HKOing Manddibuzz who can sometimes tank 2 Sludge Waves, it is also valuable for doing the most damage agaisnt various targets weak to it such as a Gyarados, Azumarill and Keldeo. Taunt is something that can be considered in the last slot. It is useful for stopping a pokemon that is trying to play around Destiny Bond with status moves, as well it can let Gengar beat some very passive defensive threats like Blissey. Substitute can be inserted onto the set, usually over Destiny Bond. It offers the utility of preventing your opponent from safely sacrificing a slower pokemon to Gengar. Though useful it forfeits either coverage or Destiny Bond's utility and also can cause Gengar to end itself through passive damage.
As this Gengar focuses only on offensive abilities maximum Speed and Special Attack optimize its effectiveness in this regard. A Life Orb is really the only choice for this Gengar's set as it demands the ability to switch moves, and also a lot of power.
Fighting, Normal, and Ground-type moves can be switched into of course, but the opponent must be pressured into using them. For example if an opposing Terrakion is facing something that does not threaten it at all its unlikely to use Close Combat when Gengar is alive. Keep this in mind when attempting high risk switch ins. The same goes for resisted moves, Landorus can easily eliminate Gengar with Psychic but Sludge Wave, Earth Power and Focus Blast bounce of it. Really, this Gengar is a high risk high reward Pokemon, use its typing aggressively to get it in and deal damage. Even with bad defenses Gengar's typing lets it deal with mono attacking Fairy-types like Clefable, and Sylveon, as well as some attackers like Scolipede. These Pokemon should be capitalized on as hard as possible. With Destiny Bond this set works well early game, as it can still perform despite counters being in tact, get it in as soon as you can.
This set is Gengar's best way to fight offense thanks to it being nearly impossible to switch into for less than bulky teams, and Destiny Bond being quite useful against them as well. Should your team need a better match up to offense this set is Gengar's best bet. Aegislash really likes it when you remove ghost counters such as Bisharp and Mandibuzz with Destiny Bond. Gengar tends to be at home on more offensive teams, its speed, power, utility and maverick like nature, along with being able to spin block are appreciated. Pair it alongside big powerful attackers like mega Gardevoir, Keldeo, Terrakion, Mega Medicham, Mega Mawile and other juggernauts for maximal hyper offensive power.
Gengar has a couple of miscellaneous coverage options that can beat some specific pokemon, such as Energy ball, Psychic, and Dazzling Gleam but these moves limited application compared to the versatility and strength of Gengar's other options. A Choice Specs set thanks to Gengar's coverage and the lack of resistances to just Ghost-type moves may seem appealing, however it requires a hell of a lot of support to function. Hung out to dry against Pursuit and Sucker Punch users, as well as any strong prioirty or Choice Scarf user in general make it quite easy to check or trap. Despite these failings it can beat pretty much every counter with coverage, or Trick and the power behind Choice Specs makes it very hard to switch into. Overall it is inefficient compared to the other sets, but still usable. A Choice Scarf set can be used and can capitalize on Gengar's immunity to Normal-type moves to reliably revenge kill Extremespeed users however these are not the biggest threats in the metagame and overall it is pretty damn weak. Pain Split is an option that can let Sub Gengar recover health, affording a Life Orb in most situations too. As well it can hassle some defensive pokemon like Chansey or Clefable pretty well discourgaing healing, but utility Life Orb Gengar fails to be as effective against stall as Black Sludge, nor as effective as all out Destiny Bond attacker against offense so its a situational middle ground.
Checks & Counters
**Heatran**: Specially Defensive Heatran is immune to burns, takes Shadow Ball quite well, and in retaliation Lava Plume does enough to force Gengar out. However it is narrowily 2HKOed by Life Orb Focus Blast.
**Bulky Pursuit Users**: Bisharp and Tyranitar are both capable of trapping Gengar with Pursuit, which is an issue, though the right coverage moves from Gengar as well as Will-O-Wisp can deter them
**Assault vest users**: Conkeldurr, Raikou, Escavalier, Tyranitar, Tornadus-T and other Assault Vest users really ruin Gengar's day, unless they can be difused with Substitute + Disable Gengar is fighting a losing battle. Of all typical Assault Vest most are crippled by a Will-O-Wisp burn however.
**Strong Choice scarf users**: Garchomp, Tyranitar Terrakion, Excadrill, Landorus-T, and what have you are all quite good checks to a Gengar that is not behind a substitute as they all cleanly outspeed and KO. Tyranitar is especially troubling as it effortlessly traps and KOs Gengar if it can get in for free.
**Strong priority moves**: Scizor, Talonflame, and other powerful Priority users like these have no trouble checking Gengar due to its frailty. Sucker Punch users may seem like a good check but no Gengar set should eschew a countermeasure to this move whether it be Substitute, Destiny Bond, or Will-O-Wisp.
**Fast Offensive Checks**: Thundurus, Alakazam, and Greninja can easily check Gengar due to its bad defenses