This list briefly summarizes the roles and abilities of common and significantly impactful Pokemon in the ADV OU metagame. 
By Umby, Triangles, and shrapn3l
Aerodactyl
Abilities: Pressure / Rock Head
Base Stats: 80 HP / 105 Atk / 65 Def / 60 SpA / 75 SpD / 130 Spe
Description 
While its movepool is rather limited, Choice Band makes Aerodactyl  viable as an OU threat. Combined with its typing and blistering speed,  it has just what it needs to be the best cleaner and one of the best  revenge killers in the metagame. Aerodactyl is frail, but its offense  makes for an excellent defense. When it gets in, its imposing offensive  presence will usually force whatever 
you've it's switched into to switch out.  Because of its move coverage and 
Speed it
,(comma) makes an excellent revenge  killer for common offensive threats, 
like such as Celebi, Raikou, Superachi, and  Dragon Dance Tyranitar. However, Aerodactyl truly shines in the  endgame, where its 
Speed and strength allow it to pick off weakened  Pokemon. Rock Slide's 30% flinch rate and STAB makes Aerodactyl even  more efficient in this role, giving it a chance to get past even healthy  bulky 
Water
-types and 
Rock resist
ances in a pinch. Although it can't  actually straight up counter much of anything, it does resist anything  standard Gyarados can throw at it, which is useful considering how few  true counters there are for Dragon Dance Gyarados. 
Blissey
Abilities: Natural Cure / Serene Grace
Base Stats: 255 HP / 10 Atk / 10 Def / 75 SpA / 135 SpD / 55 Spe
Description 
The best special wall and cleric available in OU, Blissey won't be going  down too soon after it makes its appearance. Albeit it is potential  setup bait, 
receiving multiple Seismic Tosses/Ice Beams can take their  toll and 
you can easily be crippled by Thunder Wave or Toxic if you're  too careless it can easily cripple careless foes with Thunder Wave or Toxic. Foregoing Aromatherapy/Heal Bell, Wish is always a welcome  support asset to any team and Calm Mind Blissey can also be a scary,  off-color setup if you weren't expecting it. Special sweepers should  always have a plan in mind for removing this menace if they want to be  successful.
Breloom
Abilities: Effect Spore
Base Stats: 60 HP / 130 Atk / 80 Def / 60 SpA / 60 SpD / 70 Spe
Description 
This mellow mushroom deserves mention for having an accurate sleeping  move with an actual offense behind it (the only other accurate sleepers  being Smeargle and Butterfree, neither of which have great attacking  stats). After putting something to sleep with Spore, Breloom can bust a  sizable hole in things with Focus Punch, even some of the 
things Pokemon that  resist it. It doesn't have too many other moves to run an offense with  afterwards, but it can stall with Substitute + Leech Seed until  something is forced to take a Focus Punch, and can utilize Swords Dance +  Sky Uppercut/Brick Break to some effect, with a bit of support. It's a  bit of a "one-turn impact" Pokemon, but it can dish out the hurt if you  sleep on it. Pun fully intended.
Celebi
Abilities: Natural Cure
Base Stats: 100 HP / 100 Atk / 100 Def / 100 SpA / 100 SpD / 100 Spe
Description 
Celebi, to say the least, is versatile. On defense
,(comma) it can deter certain  threats,
 like such as Snorlax or Suicune, with Leech Seed, force switches from  dangerous Pokemon with Perish Song, and makes somewhat of a special tank  when it can set up with Calm Mind (a role that is further and commonly  bolstered by Leech Seed).  Reflect and Heal Beal also make a team  player. Switch it over to offense, however, and it's a whole new ball  game. Baton Pass allows it to scout for threats, lure in Pokemon for  Magneton or Dugtrio to trap, as well as pass 101 HP Substitutes, Calm  Minds, or Swords Dances to strong offenders. It can even stand alone  with the popular iteration of Calm Mind/Psychic/Giga Drain/HP Fire, a  set that has shown particular success against many a stall team and is  hard to stop if you let it get rolling. If there's anything else to say,  for every weakness Celebi has to exploit, it's got good base stats and  just as many resistances to take advantage of to get it in safely and  pose a threat.
Claydol
Abilities: Levitate
Base Stats: 60 HP / 70 Atk / 105 Def / 70 SpA / 120 SpD / 75 Spe
Description 
Unfortunately, Claydol can't scare Spike
s users into switching like other 
spinners can (except for Forretress, if it isn't using Toxic or some  form of Hidden Power)
,(comma) but it resists both Sandstorm and Spikes to  effectively negate any residual damage as it comes in to do its job.  Later on
,(comma) Claydol's sturdy defenses gives it a few other jobs, like  setting up Reflect/Light Screen, countering Flygon, Salamence, some  forms of Tyranitar, and occasionally Gengar if you have Psychic or Light  Screen in tow. It's mostly a "threat" towards certain stall teams, as  it is possibly the toughest 
spinner to remove from play.
Cloyster
Abilities: Shell Armor
Base Stats: 50 HP / 95 Atk / 180 Def / 85 SpA / 45 SpD / 70 Spe
Description 
Of the three common Spike
s users seen in OU, Cloyster's value is being able  to escape the evil, magnetic clutches of Magneton. If one's plan for  minimizing Spike
s layers was to catch Skarmory/Forretress instead of 
spinning, that alone makes Cloyster dangerous. It's got great Defense  for coming in on Swampert and Salamence, scaring them off with STABed  Ice Beams, and while its Special Defense is horrid, Water
-types in  general make for a free switch to set up Spikes or Explode. Of course,  you can't neglect its ability to Rapid Spin either. 
With the only things  holding it back from being great being Although held back by its low HP and Special Defense  stats, it's a solid utility 
Pokemon with most of the 
things attributes you'd want from a  Spike
s user.
Dugtrio
Abilities: Sand Veil / Arena Trap
Base Stats: 35 HP / 80 Atk / 50 Def / 50 SpA / 70 SpD / 120 Spe
Description 
The ability trap and destroy other threats is a valuable trait,  especially 
since considering Raikou, Tyranitar, Heracross, Celebi, Metagross, and  Jirachi are all pretty dangerous/clutch sweepers. Once Dugtrio finds  
a way in (prediction, revenge kill, or Raikou Thunderbolt/Calm Mind) it  will simply ruin their day. Cleaning up other Pokemon 
who that are low on  health is not a bad deal either. On its own, Dugtrio is nothing special,  with its only outstanding stat being Speed, but those that can be  trapped and killed by it must be wary of it.
Dusclops
Abilities: Pressure
Base Stats: 40 HP / 70 Atk / 130 Def / 60 SpA / 130 SpD / 25 Spe
Description 
The bulkiest spinblocker in ADV OU, Dusclops is a staple on dedicated  stall teams with its excellent all-round tanking
,(no comma) and good ability in  Pressure. Dusclops can spread status with Will-O-Wisp as well
,(comma) a handy  tool for reducing the effectiveness of physical attackers. With Shadow  Ball, Dusclops is also a good answer to Gengar and Starmie as well.  However, the bandaged spinblocker is easily Pursuited for large amounts  of damage by threats such as Houndoom and the abundant Tyranitar, and is  also vulnerable to the common Sandstorm and Spikes. It is also  unfortunately 
setup fodder for the likes of Calm Mind Suicune and  Jirachi due to its low offensive prowess and lack of phazing moves.  Overall
,(comma) Dusclops is no major offensive threat to teams, apart from the  rare and very underrated Calm Mind set, but it can wall many threats and  prevent Rapid Spinners from doing their job. 
Flygon
Abilities: Levitate
Base Stats: 80 HP / 100 Atk / 80 Def / 80 SpA / 80 SpD / 100 Spe
Description 
A strong, fast, STABed Earthquake? Yes, please! From a Base 100 Attack  and an acceptable base 100 Speed, even bulky Water
-types 
may will find it tough to  deal with Flygon's attacks when piled on to residual damage. QuakeSlide  offers good coverage, as always, but Flygon can tack on Hidden Power  Bug and Fire Blast to help against Celebi and Skarmory respectively.  Flygon's typing and ability also give it a number of useful immunities  and resistances, allowing it to work well as a counter to 
Pokemon like threats such as Tyranitar and any of the usual Electric
-types (barring their Hidden  Power Ice versions).
Forretress
Abilities: Sturdy
Base Stats: 75 HP / 90 Atk / 140 Def / 60 SpA / 60 SpD / 40 Spe
Description 
Forretress may fall in line with Blissey in being potential setup bait,  but it's certainly one of the best physical walls in the game. It gets  both Spikes and Rapid Spin to take on a full utility role 
and it's  overall bulk is actually greater than Skarmory's, however it lacks a  crucial immunity to Earthquake, a phazing move (Roar/Whirlwind), and  takes extra damage from Fire
-type moves that Skarmory could normally  survive (unSTABed, of course). Unlike other spinners, Forr
etress usually  lacks means to hit Gengar on the switch, though if it takes one of the  few options that do hit Gengar, it loses Earthquake to hit Magneton and  Metagross with. When the job is done, though, Explosion is pretty neat  and can help out against last-Pokemon Curselax, among other things. This  guy really shines with some Pursuit support from the likes of Houndoom  and Tyranitar, and Forr
etress's alluring Fire weakness is amazing bait to get  them in.
Gengar
Abilities: Levitate
Base Stats: 60 HP / 65 Atk / 60 Def / 130 SpA / 75 SpD / 110 Spe
Description 
Infamous for being unpredictable, Gengar stays true to this creed 
to be and is  one of the most dangerous Pokemon in OU, especially with the rise in  Giga Drain and Will-O-Wisp usage. Gengar's big 
Special Attack allows it to do the  kind of damage some Pokemon get with the same attacks when they are  STABed and gets a number of cool immunities and resistances to make up  for its frail defenses. On top of being a premiere special attacker and  causing havoc with indirect moves 
like such as Hypnosis, Taunt and Destiny Bond,  it can even use Explosion to get rid of special walls and surprise a  few teams with Mean Look + Perish Song. Gengar's a mixed bag that  doesn't lose efficiency through spreading out its repertoire and you  never know what it's going to do. 
Gyarados
Abilities: Intimidate
Base Stats: 95 HP / 125 Atk / 79 Def / 60 SpA / 100 SpD / 81 Spe
Description 
Gyarados has some of the same threatening premises as its big brothers,  Salamence and Tyranitar, in being a Dragon Dancing, physical powerhouse,  only it has the added effect of being able to switch in and set up on  bulky 
Water-types. Its main drawback is that wields very little power with  which to launch a special attacking campaign (though it has the movepool  to do so) and that it lacks physical options to take advantage of its  highest stat with. However, coupled with Magneton (used to trap its 
number 1  counter
,(comma) Skarmory), Gyarados is one of the more potent physical sweepers  in 
ADV. With Intimidate and good all-around bulk, Gyarados can set  up multiple Dragon Dances on many threats and function as an excellent  late-game cleaner against almost any team archetype. Due to its stat  distribution, Gyarados can also go with Roar and/or Thunder Wave as  support options, perfect for complementing certain stall teams or  setting up slower sweepers, 
like such as Blaziken or Medicham.
Heracross
Abilities: Guts / Swarm
Base Stats: 80 HP / 125 Atk / 75 Def / 40 SpA / 95 SDef / 85 Spe
Description 
Heracross has to find its niche on most teams. It doesn't have the  greatest stats or typing to get in as often or as safely as Salamence,  Tyranitar, or Metagross can, but when it does find an opening, Megahorn  alone can cause grief for everyone not named Skarmory (
even Salamence  takes a sizable dent without any defensive investment). With a Choice  Band, the opposition can quickly become hard pressed to counter  Heracross without losing HUGE chunks of damage (
even Skarmory loses  around 75% of its life from Focus Punc
h), and Sub
stitute + Salac variants  are potential comeback kings. This guy can be somewhat difficult to use  effectively, but it's certainly a Pokemon to keep an eye out for.
Houndoom
Abilities: Flash Fire / Early Bird
Base Stats: 75 HP / 90 Atk / 50 Def / 110 SpA / 80 SDef / 90 Spe
Description 
Houndoom's primary use in the ADV OU metagame is to trap threats such as  Celebi, Gengar, Dusclops, and Alakazam with Pursuit and remove them  from the game to either open the opposing team up to a threatening  sweeper, or remove spinblockers so that 
Rapid spinners such as  Forretress can do their job successfully. Houndoom forms an excellent  partnership with Forretress, in that Forretress baits Fire-type attacks  for Houndoom to gain a Flash Fire boost from, and Houndoom removes  spinblockers so that Forretress can successfully do its job of removing  hazards from the field. However Houndoom struggles against 
bulky Water
-types  not named Swampert (it decimates that with Hidden Power Grass) and is  also trapped and killed by the common Dugtrio. Without Will-O-Wisp,  Houndoom will also struggle a lot against Gyarados and Salamence  (although the latter dies to the rarer Hidden Power Ice). Will-O-Wisp,  Counter, and some correct defensive investment can also 
create net a su
rprise  kill on Tyranitar. 
Jirachi
Abilities: Serene Grace
Base Stats: 100 HP / 100 Attack / 100 Def / 100 SpA / 100 SpD / 100 Spe
Description 
Offensively, Jirachi is just as dangerous, if not moreso, as Celebi.  With the same base stats, Jirachi gets the edge on offensive Calm Mind  sets with an extensive special move pool (
read as: 
it gets  Thunder/Thunderbolt and the elemental punches). Its Steel typing also  allows it to switch in on different set
s of threats and attacks, 
like such as  Choice Banded HP Flyings and Rock Slides from Aerodactyl or Salamence.  It's also got tools to play a supportive role via Wish, Light Screen,  Reflect, and Thunder Wave, if those are the kind of tools your team  needs to succeed. 
Jolteon
Abilities: Serene Grace
Base Stats: 65 HP / 65 Attack / 60 Def / 110 SpA / 95 SpD / 130 Spe
Description 
The main niches that Jolteon has over other Electrics, such as Raikou,  are the ability to Baton Pass Substitutes, Speed boosts, or simply "dry  pass" to a threat to whatever switches in on it, and also its ability  Volt Absorb, which gives it more opportunities to switch in on  Thunderbolts throughout the game. Jolteon makes a good switch-in to the  likes of Gengar and Zapdos, and also is able to counter Raikou with Roar
—Roar is a move to watch out for on Jolteon because of the amount of  switches that Jolteon forces, and as such its excellence at quickly  racking up Spikes damage. Jolteon can also support its team with Wish.  However, Jolteon is affected by all forms of passive damage and status,  and also lacks overall bulk, so it often struggles to last in longer,  slower-paced games. Overall, Jolteon is a very dangerous Pokemon with  both offensive and supporting prowess. 
Magneton
Abilities: Magnet Pull / Sturdy
Base Stats: 50 HP / 60 Atk / 95 Def / 120 SpA / 70 SpD / 70 Spe
Description 
By itself, Magneton's contribution as a threat is merely to trap and  destroy Skarmory and Forretress. Extend the scope of things, and  Magneton's threat clears the way for other threats, 
like such as Snorlax or  Heracross, to lay waste to the opposition. Combining this with Dugtrio  creates an infamous duo (an oxymoron?) that can clear out additional  threats that would otherwise hinder your sweepers, such as Tyranitar,  Celebi, or Jirachi. Magneton is a decent 
Sleep Talker RestTalk user as well, and can  serve as a Gengar and somewhat of a Zapdos counter as such.
Medicham
Abilities: Pure Power
Base Stats: 60 HP / 60 Atk / 75 Def / 60 SpA / 75 SpD / 80 Spe
Description 
With Pure Power, Medicham reaches a maximum, unboosted Attack stat of  480, which is more than even Slaking can boast. It shares the same boat  as Heracross, in finding a proper place to make itself known, but when  it does, it hits HARD 
can and can be just as tough to defend as its  Bug/Fighting cousin. With a Choice Band, Focus Punch from this monster  can 
kill KO Skarmory with a good damage roll. It also gets Bulk Up and  Recover, for a little bit of staying power, as well as Baton Pass for  some variation.
Metagross
Abilities: Clear Body
Base Stats: 80 HP / 135 Atk / 130 Def / 95 SpA / 90 SpD / 70 Spe
Description 
Metagross very rarely ends up being a huge threat on its own, 
since  things like as walls such as Milotic, Swampert and Forretress are on every team, but it  is the reason that every team needs a bulky 
Water
-type, even more so than the  likes of Aerodactyl, Tyranitar, and Salamence, 
who which have other counters 
 in Pokemon like such as Claydol. Even Skarmory, whose only real threats to  Metagross are impending Spikes and Whirlwind/Roar, is rather susceptible  to attack boosts or even crit
ical hits when taking powerful, Choice 
Banded  Meteor Mashes. The most threatening thing about Metagross is certainly  Explosion. Metagross rarely pulls off a sweep on its own, but it is  incredibly good at clearing the way for one of your other threats to get  off a sweep. In cleaning the way for other threats, outside of its  powerful Explosion, Metagross also has numerous options for targeting  numerous obstacles
—HP Grass for Swampert, HP Fire for Forretress,  Thunderpunch for Skarmory and Gyarados, and Psychic or Pursuit for  Gengar. Use this metal monster to place dents in your opponents team and  drill holes with a follow-up sweeper.
Milotic
Abilities: Marvel Scale
Base Stats: 95 HP / 60 Atk / 79 Def / 100 SpA / 125 SpD / 81 Spe
Description 
Good HP, great Special Defense and Marvel Scale make
s Milotic an  excellent and very solid bulky 
Water
-type. It does very typical 
Water-type  things, albeit access to Hypnosis is a plus for putting down an incoming  Snorlax or Suicune (
watch out for Sleep Talk) and Recover gives it an  annoying amount of longevity. Definitely worth consideration on any  stall team, though if you just need a decent way of dealing with  Salamence or just a way to absorb status, you can't go wrong here.
Porygon2
Abilities: Trace
Base Stats: 85 HP / 80 Atk / 90 Def / 105 SpA / 95 SpD / 60 Spd
Description
Porygon2's solid stats and rare ability allow it to fill a unique role   in the ADV OU metagame.  Its movepool is nothing spectacular, but it is   allotted the excellent coverage of the BoltBeam combo, and has access  to  Recover, which coupled with its good all-around bulk and huge base  105  Special Attack allows it to stick around for a long time and do  some  decent damage.  Although Porygon2 cannot use their Intimidate  against  them as it can in later gens, it is still an excellent check  for both  Dragon Dance Salamence and Gyarados, taking little damage from  their  attacks and OHKOing back with Ice Beam or Thunderbolt  respectively.   Thanks to Trace, Porygon2 is also a perfect switch-in  for slightly less  prominent threats
 like such as Flygon, Houndoom, and Jolteon,  copying their  abilities and becoming immune to their strongest STAB  attacks.  Perhaps  most important for Porygon2 in today's metagame, it  is guaranteed to  revenge kill the incredibly common Dugtrio by tracing  its Arena Trap,  making it an excellent partner for Pokemon 
like such as Dragon  Dance Tyranitar  or Choice Band Heracross, the likes of which Dugtrio  otherwise causes  major problems.  Porygon2 also has access to a few  good supports move in  Thunder Wave and Toxic, and can alternatively  work as a decent 
set-up  sweeper with Sharpen and Return, scaring off  
Pseudo phazers 
like such as Skarmory  and Suicune with powerful, super-effective  Thunderbolts.         
Raikou
Abilities: Pressure
Base Stats: 90 HP / 85 Atk / 75 Def / 115 SpA / 100 SpD / 115 Spe
Description 
Raikou falls short of the successes of Celebi, Jirachi, and Suicune in  recent times, as its typing and defenses neither allow it as many  opportunities to switch in nor do they allow for it to be able to take  any status and remain as composed. 
Nevertheless, Raikou is one of the  fastest Calm Minders in the ADV OU tier and certainly one of the more  dangerous ones. STABed Thunderbolt is always a terror to defend against,  due to the risk of paralysis, and HP Grass and Ice are there to back it  up against Ground types, as usual. 
Regice
Abilities: Clear Body
Base Stats: 80 HP / 50 Atk / 100 Def / 100 SpA / 200 SpD / 50 Spe
Description 
Having STAB on even one move in an actual BoltBeam combination is pretty  big on its own. Outside of legitimate special walls, such as Blissey,  Snorlax, or opposing Regice, STABed Ice Beam backed by a strong  Thunderbolt can cause trouble for most teams, as they 
may might find they are  unprepared for it. Aside from its special attacking prowess, it also has  access to a few surprises, 
like such as Explosion and Focus Punch to make life  hard on aforementioned walls. Not a bad deal for a Pokemon whose main  purpose is to be a wall and not a sweeper.
Salamence
Abilities: Intimidate
Base Stats: 95 HP / 135 Atk / 80 Def / 110 SpA / 80 SpD / 100 Spe
Description 
A good offensive base stat distribution, a 
good solid offensive movepool, and  access Dragon Dance is all that's really needed to make this guy a  relevant threat. Each team knows instinctively to carry a bulky 
Water
-type  with Ice Beam for Salamence in particular, as it will crush heads by its  lonesome later in the game if not properly checked. Don't sleep on it  as a support role either. Dragon/Flying offers a number of great  resistances to use for defense. Paired with Wish, you've got a pretty  sturdy tank with a surprising amount of longevity.
Skarmory
Abilities: Keen Eye / Sturdy
Base Stats: 65 HP / 80 Atk / 140 Def / 40 SpA / 70 SpD / 70 Spe
Description 
The undisputed, #1 physical wall in the game. It's renowned for it's  lack of physical weakness, multitude of physical resistances, and of  course the great Defense stat to back it up. It easily comes in on most  physical threats to set up Spikes and uses Whirlwind/Roar to force  residual damage on the opposing party. One must be wary of bringing in a  Pokemon that allows Skarmory to set up, as the longer it lives, the  more Spikes it can set up, and the more damage you
r team will take.
Slaking
Abilities: Truant
Base Stats: 150 HP / 160 Atk / 100 Def / 95 SpA / 65 SpD / 100 Spe
Description 
Choice Band Slaking is a true terror that can OHKO a lot of Pokemon.  Even those 
who that resist its moves will find it tough to switch in too  often. Paired with Magneton, simply spamming Shadow Ball can often be  enough to make dents in everything until Gengar or Dusclops are gone.  Fortunately, Truant gives you some breathing room to plan your defense  in the next turn, but Slaking's presence gathers momentum very quickly.  It's not seen often, due to its difficulty in use, but if you've got a  Pokemon with Protect or a fast Substitute... make sure you keep it alive  when this thing rears its head.
Snorlax
Abilities: Immunity / Thick Fat
Base Stats: 160 HP / 110 Atk / 60 Def / 65 SpA / 110 SpD / 35 Spe
Description 
Snorlax has fallen a bit from its original glory, what with the common  Sand Stream negating Leftovers recovery, thus hindering its prowess  (somewhat) as a special wall, but any team not equipped to handle it  will find themselves tumbling on a downhill slope. 
The existence  Snorlax's premier Curse set forces every team to have at least one way  of dealing with it, as by the time 
of the it sets up a second Curse, if you haven't  scared it off already, it's probably too late. The problem with this set  is that you're forced to choose between Earthquake and Shadow Ball as  secondary attacks
—one leaves it helpless against Gengar while
 one the other leaves it at the mercy  of Metagross, Tyranitar, and Jirachi. That said, Snorlax has just enough  options to add a bit of mixup to its role via Fire Blast and  Selfdestruct. In this, it can act as somewhat of a lure for destroying  shared counters and clearing a path for another member of your team,  similar to HP Grass Metagross or Tyranitar. Either way, Snorlax is just  one of those Pokemon that you MUST be prepared to handle, as it's  longevity and big Attack stat allows it cause big dents in a team and  Curse can quickly make it impenetrable.
Starmie
Abilities: Illuminate / Natural Cure
Base Stats: 60 HP / 75 Atk / 85 Def / 100 SpA / 85 SpD / 115 Spe
Description 
Starmie seems to find the same reasons to be a great asset in every  generation, in that it serves valuable utility purposes in Thunder Wave  or Rapid Spin while being a premier special attacker. 
Though When it  places full focus on its offensive potential, teams could find they are  ill prepared to handle it. With great Speed and Special Attack, it makes  a great spinner, being able to scare Gengar more readily if that is the  opponent's chosen 
spinblocker, and access to Recover also helps it  stay healthy if it isn't immediately able to remove Spikes from the  fray.
Suicune
Abilities: Pressure
Base Stats: 100 HP / 75 Atk / 115 Def / 90 SpA / 115 SpD / 85 Spe
Description 
Suicune's been a big guy even since the earlier days of ADV, known for  having "NO WEAK" once it gets rolling with a few Calm Minds.  Traditionally
,(comma) it functions as a wall, given 
nice a nice defensive  distribution in its base stats and defensive tools like Reflect and  Roar. Calm Mind helps make it a special tank while simultaneously making  it an offensive threat even to those that would be its counters (it  shrugs off attacks from Snorlax and can Roar it out, outstalls Blissey,  Regice won't stand a chance without Psych Up, and Celebi might have to  deal with Ice Beam). In recent times, however, its offensive prowess has  contributed to shaking up the metagame. Factor in great bulk that  shines even without a defensive spread, a decent 
Speed stat, and a  common habit for Zapdos to run well below Suicune's max speed, and an  offensive-oriented Suicune can be quite tough to deal with. Having such  great defenses also allows for it to be a particular pain with 101 HP  Substitutes. Once it finds an opportunity to switch in on something
, such as like  a Water
-type, it can sub up to avoid potential status and begin to  wreak havoc.
Swampert
Abilities: Torrent
Base Stats: 100 HP / 110 Atk / 90 Def / 85 SpA / 90 SpD / 60 Spe
Description 
While Swampert's main appeal is being able to deal with many of  Tyranitar's movesets, it actually spreads some decent damage across the  board outside of that. 110 base Attack is a nice stat to launch a STABed  Earthquake from and the benefits of Torrent boosted Surf/Hydro Pump can  turn the tide in a 1v1 matchup. Not to mention the QuakeBeam combo  gives Swampert a lot of coverage by its lonesome. EndeavorPert is also  fun a gem that can catch a team off guard, particularly against bulky 
Water
-types with sand up, if you play your cards right.
Tyranitar
Abilities: Sand Stream
Base Stats: 100 HP / 134 Atk / 110 Def / 95 SpA / 100 SpD / 61 Spe
Description 
True to it's name, there's no question that Tyranitar reigns supreme  over the ADV OU tier. It's got great stats and typing to defend from all  different kinds of angles and an accompanying movepool that diversifies  its offense just as well. Sand Stream is also highly influential in the  metagame, as it negates Leftovers recovery, making it that much harder  for certain Pokemon to take the great damage it's dishing out. While  wielding a frightening offense via its physical options (DDTar, Physical  Boah, CBTar) that allows it to clear out a good chunk of a team by  itself, Tyranitar can also opt to cripple/destroy its teammates'  counters through mixed/special options, with moves 
like such as H
idden P
ower Grass being  viable to hurt Swampert, Fire Blast to scare off Skarmory and  Forretress, or Pursuit to get rid of Gengar. Its versatility, toughness,  and power all combine into a factor that you should always have at  least one way of handling when team building.
Umbreon
Abilities: Synchronize
Base Stats: 95 HP / 65 Atk / 110 Def / 60 SpA / 130 SpD / 65 Spe
Description 
Umbreon is a very unique threat, in that it isn't normally a threat or  counter to anything by itself. Through its common Mean Look + Baton Pass  strategy, it creates an environment were other threats can set up a  devastating offense with little risk in damage to themselves. This  leaves such things as Suicune, Snorlax, or Salamence to boost up without  any problems if you trap the right thing, though it makes a wonderful  pivot in Baton Pass chains to keep a helpless Pokemon locked in while  you beef up as well. Umbreon also has some additional support 
ability options  through moves 
likes such as Charm and Wish and can pass stat boosts of its own  via Curse. Watch out for Taunt users, though. Umbreon's poor offense  rarely warrants an attack, and thus is left helpless to Pokemon 
like such as DD  Gyarados or Gengar 
who may that might be using Taunt. Substitute users are also a  problem if they come out before 
you it can Mean Look them.
Vaporeon
Abilities: Water Absorb
Base Stats: 130 HP / 65 Atk / 60 Def / 110 SpA / 95 SpD / 65 Spe
Description 
Despite its excellent base 110 Special Attack stat, Vaporeon sees its  best use as a WishPassing defensive pivot
,(no comma) (due to its awesome 130 base  HP and ability in Water Absorb), used to provide support for teams with  powerful attackers that lack reliable recovery, such as Choice Banders  in a general sense. Vaporeon is a good answer to the likes of Metagross  and Houndoom, and can also switch in on other Water
-types such as Swampert  and Milotic and either poison them with Toxic, or set up free Wishes to  pass on. Unlike other bulky Water
-types, however, it is quite vulnerable to  repeated barrage
s or Rock Slides from Tyranitar due to its comparatively  poorer physical bulk. The aquatic kitty is also vulnerable to status as  well, and a Toxic-poisoned Vaporeon is not half as effective as it  usually would be. Also of note is Vaporeon's ability to Baton Pass. In  BP chains
,(comma) it is the common go-to for defense boosts with Acid Armor, and  with a few speed boosts it is also able to Roar out any phazers seeking  to get rid of those boosts. Its stellar HP is useful for making good  sized Substitutes as well.
Zapdos
Abilities: Pressure
Base Stats: 90 HP / 90 Atk / 85 Def / 125 SpA / 90 SpD / 100 Spe
Description 
Zapdos, despite its standout 125 Special Attack, is generally used in a  defensive role as a RestTalker, absorbing status and abusing its  excellent PP-stalling ability in Pressure. Zapdos works best when  partnered with Spikes, in that nearly all Pokemon that switch into  Zapdos are grounded, and as such sustain Spikes damage whenever  switching in. Zapdos can also work well offensively with either a purely  special offensive set
—often with Metal Sound to hit switch-ins and  make them think twice about staying in (MSdos and Spikes are a match  made in heaven)
—or a mixed offensive set which incorporates Drill Peck  to lure in and damage Celebi. Zapdos is also both a good receiver and  an excellent lead in Baton Pass chains, and is very adept at passing  Substitutes and/or Agility boosts around the team, in that its STAB  Thunderbolt frightens phazers such as Skarmory and Suicune, and it can  pass unhindered.