Weezing, The Poison Gas Pokémon. Very rarely, a sudden mutation can result in two small Koffing twins becoming conjoined as a Weezing. It loves the gases given off by rotted kitchen garbage. It will find a dirty, unkempt house and make it its home. At night, when the people in the house are asleep, it will go through the trash. It alternately shrinks and inflates its twin bodies to mix together toxic gases inside. The more the gases are mixed, the more powerful the toxins become. It also becomes more putrid. By diluting its toxic gases with a special process, the highest grade of perfume can be extracted. To Weezing, gases emanating from garbage are the ultimate feast. Where two kinds of poison gases meet, two Koffing can fuse into a Weezing over many years.

Battle Moveset

A Good Moveset for Weezing would have to be this:

Attacks:

Sludge Bomb
Haze
Will-o-Wisp
Pain Split

Items Attached:

Leftovers

Preferred Nature:

Impish or Modest

Strategy Using Weezing

A pretty straight-forward and easy to understand set. Weezing is quite simply an unmatched counter for Fighting types and a fantastic physical wall, much like Skarmory it has fantastic defence and no physical weaknesses. With Will-o-Wisp and Haze in it's move pool it also gives it's team fantastic support. Pain Split gives Weezing a lot of survivability, especially when faced against an opponent with a lot of HP and STAB Sludge Bomb hits a lot of opponents for very respectable damage.

EV Corner:

EVs: 252 HP / 84 Atk / 172 Def
Impish Nature (+Def, -SAtk)

Pretty much the standard set-up for Weezing EVs. Since Pokémon like Tyraniboah like to go with a bit of Speed to outrun Weezing and then throw up a Sub it may be worth investing a few EVs in Speed to be able to hit them with a Wisp, some people also prefer to run some Special Defence on their Weezings since Weezing can take a handful of Special Attacks, especially with the support of Pain Split.

EVs: 252 HP / 84 Atk / 172 Def
Relaxed Nature (+Def, -Spd)

Pretty much the same set-up as above but with this set-up you can run some Special Attacks on Weezing (usually over Haze or Wisp), Thunderbolt and Fire Blast are popular examples. Once again it's worth running a few Speed EVs on Weezing, -Speed Weezing ties with Brave/Relaxed Swampert (the standard), with a little speed it can outrun it. It's also worth noting that some people also like to run Special Attack EVs to give their Special Attacks a bigger punch.

Other Optional Sets

Weezing @ Choice Band
Trait: Levitate
EVs: 252 HP / 84 Atk / 172 Def
Relaxed Nature (+Def, -Spd)
- Sludge Bomb
- Explosion
- Fire Blast / Shadow Ball / Will-o-Wisp
- Fire Blast / Shadow Ball / Will-o-Wisp

CB-Zing. On a Choice Band theme team this would be an ideal choice to fill a physical wall role although on a standard team it wouldn't be of as much use. Will-o-Wisp will help your team handle physical attackers a bit easier but after using it you'll need to switch out (as is the way with other moves), Fire Blast is a nice option for hitting stuff like Skarmory and Shadow Ball can catch ghosts like Dusclops and Gengar who will wall your Sludge Bombs easily.

Weezing @ Leftovers
Trait: Levitate
EVs: 252 HP / 84 Atk / 172 Def
Relaxed Nature (+Def, -Spd)
- Sludge Bomb
- Explosion
- Fire Blast
- Will-o-Wisp / Toxic

Offensive Weezing. Fire Blast is once again used for stuff like Skarmory and the other common Steel types. Wisp can be used as a support move but since a lot of 'Bulky Waters' tend to switch into Weezing to wall it you could try Toxic to handle them more efficiently. You'll probably want a different 'main' physical wall if you intend to use this Weezing set since it's survivability isn't as high as with the normal Weezing set.

Other Optional Moves

Thunderbolt, Thunder, Fire Blast, Flamethrower, Destiny Bond, Taunt, Memento, Hidden Power [Fight], Screech, Rest.

Thunderbolt and Thunder can be used against a lot of common things that cause Weezing problems, Taunt-Gyarados is the most common example that it's used against but they also hit Water types pretty reasonably so a Water type trying to wall Weezing will be hit pretty hard (and in the case of Thunder having a 30% chance to paralyse is very appealing). Fire Blast can be used on the main set instead of Wisp or Haze and Flamethrower is a more accurate option instead of Fire Blast. Destiny Bond can be used in the same way as Explosion is used, a way to kill off an opponent before as you faint. Taunt has it's uses, stopping Snorlax from using Rest, Blissey from using Softboiled and so on but Weezing's speed isn't high enough to make particularly effective use of it. Memento, although seemingly a weak version of Explosion, can allow a team-mate to set-up easily on an opponent (such as Belly Drum Charizard), although it's use is situational and depends highly on your team. Hidden Power [Fight] is one of the effective Hidden Powers worth mentioning to use with Weezing, Tyranitar (who usually has Taunt or Substitute) never wants to be on the other end of it and opposing Rock and Steel types who try to block your Sludge Bombs won't want to be hit by it. It won't be often but Weezing could get some mileage out of Screech, especially on a more offensive set. Although it has Pain Split Rest is another HP recovery move, if you have a cleric on the team it can be of use.

Strategy Against Weezing

The best counter for Weezing is simply Milotic, with Marvel Scale Milotic absolutely loves to switch into Will-o-Wisp and loves the 30% Poison chance that comes with Sludge Bomb. With it's high Special Defence and Recover the occasional Thunder/bolt Weezing isn't anything to worry about. Guts Pokémon also like the 30% chance of Poison form Sludge Bomb as well as Will-o-Wisp, the presence of a Guts Pokémon is usually enough to make Weezing think twice about using Will-o-Wisp. Fire types are immune to Will-o-Wisp and Weezing's low Special Defence doesn't like to be hit by STAB Fire moves so Fire types are also a good choice, Camerupt and Magcargo resist Sludge Bomb as well although they're UU.

Taunt and Substitute, especially in combination with good Defence or a Poison resistance is the next best thing for countering Weezing. So long as they don't switch into Will-o-Wisp Dragon Dance Tyranitar and Gyarados counter Weezing easily, although Gyarados needs to watch out for Thunder/bolt. Substitute or Taunt combined with any Steel, Ghost, Ground or Rock type who is faster than Weezing is a is also a sure-fire Counter for most Weezings (Metagross and Gengar for example).

Bulky Special Attackers (such as many Water types) are particularly popular as Weezing counters as well and handle it pretty simply, the aforementioned Milotic, Suicune and Vaporeon are some good choices. Swampert is usually included in the list of bulky waters but it's dislike of Will-o-Wisp is a major deterrent. Weezing is weak to Psychic attacks but it's Special Defence is low enough that generally any Special attack that it doesn't resist is enough to grab a 2KO.

Contest Moveset

A good Contest Moveset for Weezing would have to be this for the Beauty Contest best with Modest, Mild, Rash or Quiet Nature:

Attacks:

Sunny day
Flamethrower
Sludge
Explosion

Items Attached:

Blue Scarf

Strategy Using Weezing

If you do the attacks in this following order you should have very few problems; 1st - Sunny day, 2nd - Flamethrower, 3rd - Sludge/Sunny day, 4th - Flamethrower, 5th - Explosion

Locations in Games

Ruby/Sapphire/Emerald Evolve Koffing Colosseum Trade from RSEFRLG Fire Red/Leaf Green Pokémon Mansion (FR), Evolve Koffing (LG)

Animé Appearences

Weezing has had a fair few Animé Appearence. Many of which, one was under the control of James in his constant battles for Team Rocket against everyone until he set it free to look after a group of Koffing. Below are major appearences by it Episode 031: Dig Those Diglett! Episode 057: The Ultimate Test! Episode 282: A Poached Ego!