At first glance, Wobbuffet appears to be a pathetic excuse for a Pokemon with awful stats, sans HP, and a movepool that's as shallow as can be. If one cares to look closer, however, Wobbuffet can be quite a threatening force. It possesses the ability to either kill any Pokemon whom it wishes with proper prediction and the combination of Encore and either Mirror Coat or Counter. It can also use Encore to make a support Pokemon complete setup fodder. Although it's almost completely shut down by Taunt (Mirror Coat and Counter ignore Taunt), it is still definitely a force to prepare for; you can suddenly find yourself without a check to a very threatening sweeper or utterly helpless to do anything as one of the opponent's Pokemon gets a free turn of set up.
The one and only set for Wobbuffet. With little prediction, or none at all if Encore is used, Wobbuffet can guarantee at least one kill against a Choiced Pokemon (preferably a Pokemon with Choice Scarf). Choose Counter if your opponent is clearly a Choiced physical attacker, or Mirror Coat if it's a Choiced special attacker. If it's a Pokémon without a Choice item, simply use Encore and proceed from there since your opponent can't switch out. Encore can also work to your benefit if the opponent chooses to use a stat up move, as this will allow a free switch in for one of your Pokemon and at least one turn of set up. Encore is especially effective against defensive Pokemon, such as Lugia and Blissey, as the best they can do is use Toxic on Wobbuffet, and the move is rare on Lugia. Forcing a Pokemon to repeat a move while preventing them from switching is one of the most sadistic, and effective, strategies in Pokemon. Wobbuffet can also switch into a lead Choice Scarf Darkrai's Dark Void, forcing it to struggle to death. This can be risky, because if Darkrai uses Trick, Wobbuffet is crippled, and if Darkrai uses Dark Pulse, then Wobbuffet will take a massive amount of damage (and it cannot use Mirror Coat, as Darkrai is immune to it).
Both Safeguard and Tickle will be helpful as your last move. Safeguard is obviously there to prevent Wobbuffet from being crippled by status ailments and can help it support the team at the same time. The only downside is that Wobbuffet is very slow and will most likely be statused before it can use Safeguard. Still, Encoring a status move and using Safeguard can be an effective way to set up a sweeper. With Tickle, Wobbuffet can become an effective wallbreaker when paired with a user of Pursuit (such as Tyranitar or Scizor). Tickle Wobbuffet's main targets are Lugia and Blissey. Once Lugia is Tickled and Pursuited to death, most stall teams will be vulnerable to sweeps from deadly physical setup sweepers, like Rayquaza or Garchomp.Team Options & Additional Comments >>>
Wobbuffet's large and diverse movepool consists of a whopping eight moves. Besides the absolutely useless Splash, the only moves not covered above are Destiny Bond and Charm. Destiny Bond may seem like an appealing option since it allows you to take one more opponent down when you're low on heath, but Wobbuffet does not have the Speed to pull this off effectively and thus it should only be used on Trick Room teams. Charm may appear an interesting way to set up on physical attackers, such as Groudon and Rayquaza, but by the time Wobbuffet switches in to them, they will usually have already set up, OHKOing Wobbuffet before it can use Charm.
Checks and Counters
By definition, a proper counter must be able to switch in against whatever it is they are trying to counter. As mentioned, Wobbuffet's ability prevents the opponent from switching if they lack the moves Baton Pass or U-turn or aren't holding a Shed Shell, which means it essentially has no real counters. So if you should meet this Pokemon during one of your battles, what can you do against it?
Taunt is probably the most effective defense against the blue blob. It will completely shut down Wobbuffet for a few turns, and all it can do is Counter and Mirror Coat for no damage. The most effective users of Taunt against Wobbuffet are Tyranitar, Mew, Mewtwo, and Darkrai, as they can use the time to set up. Sleep-inducing moves are also a temporary solution. By putting it to sleep, you can force it to switch out, use the opportunity to stat boost, or simply hit it with your strongest moves and hope you can score a KO before it wakes up. The Trick + Choice item strategy is also effective since it will limit it to only one move and therefore ruin its usefulness; just make sure you do this on the switch, or Wobbuffet can Encore Trick. A particularly effective Trick-user is Lugia, a Pokemon who Wobbuffet commonly switches in on. Toxic will help only if Wobbuffet is the last Pokemon on the team. Otherwise, it will simply Encore your Toxic and switch out to a cleric, one of the many Pokemon immune to Poison-type moves, or Wobbuffet will simply use Safeguard to set up a sweeper. However, Toxic Spikes can hinder Wobbuffet's jobs in revenge killing and setting up sweepers, as Aromatherapy can not get rid of them. Finally, Roar and Whirlwind will force it to switch out, although it will still come back to haunt you later in the battle. Never attempt to Roar or Whirlwind Wobbuffet if he is already in on said phazer, or else Wobbuffet will Encore your last used move, thanks to phazing moves' negative priority.
As mentioned, Baton Pass and U-turn are the only moves that have the ability to allow users to escape from Shadow Tag's grip. U-turn is super effective, but if you use it and Wobbuffet uses Counter in the same turn, the Pokemon who switches in will receive a pretty nasty dent (provided that they are not a Ghost-type). Scizor is the best user of this, so if you use U-turn on a full health Wobbuffet, make sure you have a Ghost-type Pokemon, or Wobbuffet has a chance of surviving and KOing the next Pokémon to be switched in. Giratina is usually the best choice here. Shed Shell also allows you to switch, but the only practical Uber users of it, Blissey and Lugia, will not enjoy losing Leftovers recovery.
Since Mirror Coat is a Psychic-type move, it will not affect Dark-types, which means Dark-type Pokémon can pound Wobbuffet with special attacks without fear of getting Mirror Coated back. Darkrai is a particularly good choice for this when battling in Ubers. Tyranitar also falls into this category but it must be using Dark Pulse and special Tyranitar isn't as useful in Ubers as it is in standard. Choice Band Tyranitar can also use Crunch or Pursuit against it. Likewise, Ghost-types are unaffected by the Fighting-typed Counter and can hit it with physical moves. Giratina-O can slam Wobbuffet with physical attacks. Spiritomb, being both Dark- and Ghost-type, is completely immune to both Counter and Mirror Coat; however, it is unlikely that any intelligent trainer will leave their Wobbuffet in against a Dark- and/or Ghost-type Pokémon. Dugtrio with Toxic can also turn the tables on Wobbuffet, as Wobbuffet will be unable to switch out and will slowly die off from Toxic damage. Extremely hard hitters, like Choice Specs Kyogre or Choice Band Ho-Oh, can bring Wobbuffet down, but if Reflect or Light Screen are in play then Wobbuffet will probably come out on top. Choice Specs Palkia, Choice Specs Dialga, and Choice Band Garchomp can be a nasty surprise to Wobbuffet, since these Pokemon often carry Choice Scarf, and their Dragon-type moves can 2HKO Wobbuffet with an attack-boosting Choice item.
A common mistake in using Wobbuffet is to send him in on common Uber Spikes users, like Forretress. This is not a good idea, because Encoring Spikes will almost ensure that the opponent can set up 3 layers of Spikes; thus all grounded Pokemon on the team will take a whopping 25% of their health by just switching in.
In the end, you will probably lose one Pokemon (especially if it is a Choice Scarf user) to Wobbuffet simply because you weren't expecting it. If this happens at the right time, this can put you at risk of being destroyed by powerful sweepers, such as Darkrai and Garchomp. Thus, it is often best to keep your Choice Scarf revenge killers (such as Choice Scarf Palkia) hidden until Wobbuffet is significantly weakened, because losing such vital revenge killers can potentially cost you the game.