QC: fleggumfl / bludz / Tokyo Tom
GP: The Dutch Plumberjack / frenzyplant
Mamoswine is a solid wallbreaker in OU thanks to its great Attack combined with an excellent offensive typing, that makes it difficult for many teams to switch into. Its typing coupled with decent overall bulk allows it to work as a great check to common Electric-types in the tier. A decent ability in Thick Fat also gives it valuable resistances to Ice- and Fire-type moves and grants it more opportunities to switch in. However, Mamoswine sits at a low Speed tier that, in tandem with relatively low bulk, leaves it a glass cannon that can't outpace premier OU threats. It also faces competition from Weavile, which boasts a better Speed tier as well as STAB Knock Off, though Mamoswine has a more useful Ice / Ground typing as well as more power and bulk. Mamoswine faces further competition from Kyurem-B, which has much more bulk and versatility in addition to much wider movepool and a solid niche as the only specially based Ice-type in OU. Lastly, Mamoswine struggles to break past certain Steel-types, such as Skarmory, Ferrothorn, and Mega Scizor.
move 1: Ice Shard
move 2: Earthquake
move 3: Icicle Crash
move 4: Superpower / Freeze-Dry / Stealth Rock
item: Life Orb
ability: Thick Fat
nature: Adamant / Jolly
evs: 252 Atk / 4 SpD / 252 Spe
Ice Shard is mandatory, as it allows Mamoswine to revenge kill Flying-, Dragon-, and Grass-types such as Tornadus-T, Mega Altaria, and Serperior and pick off weakened threats. Earthquake is Mamoswine's most powerful STAB move and offers nice coverage in tandem with its Ice-type attacks. Icicle Crash is its preferred Ice-type option, coming with a decent flinch chance with imperfect accuracy. Superpower allows Mamoswine to eliminate more physically defensive Ferrothorn variants which otherwise wall Mamoswine. Knock Off is a decent option, as it allows Mamoswine to remove items from its few switch-ins to aid in wallbreaking and cripple said switch-ins for the rest of the match. Freeze-Dry gives Mamoswine the ability to lure in and KO bulky Water-types that it otherwise struggles with. Stealth Rock can be used for Mamoswine to act as an offensive entry hazard setter, due to its ability to threaten common setters such as Garchomp, Heatran, and Landorus-T.
Maximum Attack and Speed investment allows Mamoswine to hit as hard and fast as possible. A Jolly nature allows Mamoswine to outspeed Bisharp, Breloom, and Timid Heatran. An Adamant nature can be run for a considerable increase in power, exemplified by a high chance to 2HKO Skarmory with Icicle Crash, Mega Scizor with Earthquake, and OHKO Tornadus-T with Ice Shard after Stealth Rock, but this comes at the expense of failing to outspeed the aforementioned threats. Thick Fat is the ability of choice, as it gives Mamoswine the ability to work as a check to certain Electric-types and switch into some Ice- and Fire-type moves. Life Orb bolsters Mamoswine's overall power. If running Freeze-Dry, a spread of 240 Atk / 16 SpA / 252 Spe along with a Naughty or Naive nature gives Mamoswine the ability to 2HKO Rotom-W and Slowbro, which it otherwise struggles with.
It's best to utilize Mamoswine as an early- or mid-game wallbreaker. Mamoswine can be used to pressure common entry hazard setters, such as Landorus-T and Heatran, as well as hazard removers, through its STAB combination and power. Bring Mamoswine in through use of Volt Switch and U-turn or double switching, as its bulk is decent at best. Good prediction is necessary to maximize Mamoswine's potential due to its below average Speed.
Mamoswine is often found on offensive teams that appreciate its ability to threaten bulky Ground- and Water-types and pressure Heatran with its mixed set. Magnezone can trap and eliminate Skarmory, Scizor, and Ferrothorn while also offering Volt Switch support. Flying-types such as Mega Pinsir and Talonflame appreciate Mamoswine's ability to lure in and KO Rotom-W and Quagsire and eliminate checks such as Garchomp, Landorus-T, and Heatran. Mega Charizard X appreciates Mamoswine's ability to pressure bulky Ground-types such as Hippowdon and Landorus-T and its ability to eliminate Slowbro and Quagsire with Freeze-Dry. In return, Mega Charizard X can beat the Steel-types Mamoswine struggles with. Serperior benefits from Mamoswine's ability to threaten Tornadus-T, Mega Altaria, Heatran, and Amoonguss and can break down bulky Water-types in return. Heatran can pressure the Steel-types that wall Mamoswine while taking advantage of its ability to lure in and KO threats such as Rotom-W and Slowbro. Klefki provides speed control to alleviate Mamoswine's Speed issues and forms an entry hazard-stacking core with it if you run Stealth Rock. Ferrothorn provides a switch-in for foes such as Mega Gyarados and Azumarill while providing Stealth Rock or Spikes support to aid Mamoswine in its wallbreaking.
Icicle Spear can be run to bypass Focus Sash and Substitute users as well as Multiscale Dragonite and Yache Berry users. Choice Scarf gives Mamoswine better revenge killing capabilities and a surprise factor at the expense of power and the ability to change its moves. A dedicated Stealth Rock lead set utilizing Focus Sash and Endeavor can be used with Oblivious as its ability.
Checks and Counters
**Priority Move Users**: Azumarill, Scizor, and Breloom can all threaten Mamoswine with their super effective priority moves, though Breloom is a more situational threat because it needs to run Focus Sash and Mamoswine must be an Adamant variant. Mamoswine also takes a large chunk of damage from Bisharp's Sucker Punch and Talonflame's Brave Bird.
**Revenge Killers**: Due to its low Speed tier, Mamoswine is easily outsped Pokemon on more offensively oriented teams and fast, hard-hitting Pokemon that can tank an Ice Shard, such as Mega Lopunny, Conkeldurr, Starmie, Keldeo, and Mega Diancie.
**Bulky Water-types**: Slowbro, Rotom-W, Manaphy, and Quagsire can easily tank either of Mamoswine's typical STAB attacks and wear it down with their own STAB attacks or status effects. However, they can be eliminated through the use of Freeze-Dry.
**Steel-types**: Skarmory and Ferrothorn are big trouble for Mamoswine. Skarmory is immune to Earthquake and can tank an Icicle Crash and retaliate with Iron Head or Counter, and while Ferrothorn is hit neutrally by Mamoswine's STAB attacks, it can wear it down with Leech Seed or KO it with Gyro Ball. Mega Metagross can outrun Mamoswine and KO it with Meteor Mash, and Klefki can use Magnet Rise to avoid Earthquake and chip away at Mamoswine. Scizor can weaken it with Bullet Punch, and Excadrill and Jirachi can outspeed it and KO it with Iron Head.