Moves
Alolan Muk naturally avoids a 2HKO from Mega Gengar, Lunala, and Mega Mewtwo Y when healthy enough, and it can even take multiple attacks when equipped with an Assault Vest. This makes Alolan Muk an effective Pursuit trapper that can guarantee said threats' removal.
Though many Pokemon in Ubers hold irremovable items, Knock Off can punish a large number of switch-ins like Ferrothorn and Magearna that dislike losing their item. Knock Off is generally the most spammable move when Alolan Muk isn't attempting to Pursuit trap something, as foes with irremovable items that want to switch into it risk getting poisoned due to Poison Touch.
Shadow Sneak gives Alolan Muk some usefulness against offensive teams by letting it pick off weakened Marshadow and Ultra Necrozma. More importantly, this move significantly improves Alolan Muk's matchup against Deoxys-A, as the latter is forced to predict between attacking Alolan Muk first on a predicted Pursuit or switching out on Alolan Muk's Shadow Sneak, which OHKOes it before it can move.
Clear Smog is quite weak due to Alolan Muk's low Special Attack and lack of investment, but it is a crucial tool for Alolan Muk to weaken boosted Geomancy Xerneas and Calm Mind Arceus formes in a pinch. When Alolan Muk is no longer needed, this move also comes in handy against Primal Groudon and Arceus-Ground by preventing them from setting up.
Poison Jab enables Alolan Muk to defeat Life Orb Yveltal in a one-on-one situation, 2HKO Xerneas, and OHKO the rarer Tapu Lele. Combined with Poison Touch, Poison Jab also has a good chance to poison the foe.
Set Details
Maximum HP investment increases Alolan Muk's mixed bulk, and combined with 28 Defense EVs, Alolan Muk can avoid a 2HKO from Life Orb Deoxys-A from full HP.
80 Attack EVs with an Adamant nature give Alolan Muk enough power to OHKO Mega Gengar on its switch with Pursuit. The rest of the EVs are invested into Special Defense to make Alolan Muk more challenging for Lunala and other special attackers to take down.
Maximum Attack EVs can be considered to 2HKO Lunala with Shadow Shield intact with Pursuit. A stronger Pursuit also has better odds to 2HKO Mega Mewtwo Y.
Poison Touch gives Alolan Muk's contact moves a 30% chance to poison the target, which makes it hazardous for Alolan Muk's checks like Primal Groudon to directly switch in.
Usage Tips
Alolan Muk boasts high special bulk with the given investment and Assault Vest. Pokemon like Arceus-Dark, Mega Gengar, and Lunala will struggle to take down healthy Alolan Muk with a few hits, and the latter two can be easily weakened or removed once Alolan Muk has switched in safely.
Complete lack of recovery means Alolan Muk will inevitably be worn down as it continues to pivot into attacks. Unless the team has Wish support, Alolan Muk's health management will be important, so avoid switching into neutral attacks from Pokemon like Arceus-Water and taking damage from entry hazards. Especially if Alolan Muk has other important tasks to fulfill, such as trapping Deoxys-A, combating and weakening Yveltal for teammates, and remaining as an emergency stop to Geomancy Xerneas, it won't be able to keep itself healthy for multiple foes. This means even switching into Toxic users can be a risky move unless it is pivoting into an extremely passive foe like Blissey.
However, opponents will often try to bait in Alolan Muk, and most teams will have at least two Pokemon that can take advantage of its tendency to reactively switch in. Alolan Muk especially suffers from the wide range of Pokemon that can threaten it in a one-on-one situation, and it is punished even more harshly if it runs into a check or counter after taking entry hazard damage.
Be mindful about the significance of Alolan Muk and Pokemon it has to check. Teams that will be reliant on Mega Gengar or Lunala to gain an upper hand against slower teams that Alolan Muk commonly fits on will try to preserve them until it is weakened throughout the game or they have benefited a lot from baiting in Alolan Muk, double switching, and reversing momentum.
Alolan Muk can exercise less caution against slower teams and defensive teams where there will be fewer offensive checks and more Pokemon like Blissey that also tend to reactively switch into their checks. These teams also tend to lack a Pokemon that Alolan Muk has to remain healthy to handle, so fully take advantage of Knock Off's item removal and Poison Touch in this matchup.
Do not overlook Shadow Sneak's usefulness. In an emergency, Shadow Sneak can do minor damage and poison a foe at the same time, so Alolan Muk will have two chances to poison a foe setting up on it before going down. Shadow Sneak can also pick off weakened Psychic- and Ghost-types, preventing the likes of Ultra Necrozma and Marshadow from damaging a revenge killer before going down.
While Alolan Muk's matchup against Mega Gengar is generally advantageous, some Mega Gengar variants with Will-O-Wisp can circumvent this. Substitute variants can also escape from Alolan Muk, as Substitute will take damage for Mega Gengar as it switches out. This means being overly reliant on Alolan Muk to compensate for the team's vulnerability to Mega Gengar isn't advised. Alolan Muk also struggles to effectively trap Gothitelle, as it is slower than Gothitelle, so it will be neutralized by Charm before it can KO back.
Team Options
Balanced and defensive teams can employ Alolan Muk to provide themselves with security against Ghost-types. Teammates like Arceus-Fairy, Lugia, and Mega Slowbro, which are vulnerable to Mega Gengar, benefit from Mega Gengar's absence and Alolan Muk making Lunala hesitate before taking advantage of them. These Pokemon may also struggle to properly deal with Toxapex, and Alolan Muk can absorb Toxic Spikes on the switch when given a chance. In return, Lugia and Mega Slowbro are capable of checking Primal Groudon, which may set up as Alolan Muk is forced out. Arceus-Fairy can check threats like Yveltal and Marshadow and prevent Calm Mind Arceus-Dark from fully setting up on Alolan Muk lacking Clear Smog.
Entry hazard support will come in handy, as Facade Mega Salamence will struggle to take advantage of status induced by Alolan Muk and keep itself healthy at the same time with Stealth Rock on the field. Defensive Ho-Oh can be also a nuisance to this set, and Stealth Rock can be helpful for this reason as well. Primal Groudon and Arceus-Fairy can be appropriate choices for Stealth Rock setters. Primal Groudon can take advantage of Steel-types that try to wall Alolan Muk, and with Alolan Muk potentially poisoning support Arceus formes, it can 2HKO them even when lacking offensive investment. Arceus-Fairy's ability to threaten Giratina-O and Mega Sableye while setting Stealth Rock will come in handy to pressure certain balance and defensive teams. In return, Alolan Muk can remove Leftovers from Magearna to make it easier for Arceus-Fairy to wear down.
Defensive teams can use Chansey or Blissey to better check support Arceus formes and Xerneas. Chansey especially appreciates Alolan Muk's ability to remove Leftovers from Steel-types and Pursuit trap Mega Gengar, and it can keep Alolan Muk healthy with Wish support.
Entry hazard removers are needed to prevent Alolan Muk from getting worn down by entry hazards. As a single switch when Stealth Rock is on the field can lower the chance that Alolan Muk checks Deoxys-A and Geomancy Xerneas in a pinch, entry hazard removers like Ho-Oh, Giratina-O, and support Arceus formes are important partners. These Pokemon are also effective pivots to Primal Groudon. Choice Scarf Xerneas is also a considerable option, as it must be wary of Mega Gengar and can take down Ultra Necrozma, which Alolan Muk needs too much prior damage to reliably take down with Shadow Sneak.