Mamoswine

Mamoswine’s unique typing, granting it a nearly unresisted STAB combination, a neutrality to Stealth Rock, and an immunity to sand and hail, makes it a potent wallbreaker in DPP OU. Ice / Ground is only resisted by Bronzong, while Mamoswine’s base 130 Attack hits the many common Pokemon weak to these moves such as Jirachi, Tyranitar, Latias, Heatran, and Breloom really hard. Mamoswine also has strong priority in Ice Shard, allowing it to revenge kill Dragonite, Flygon, and Latias effectively. Mamoswine is a potent user of Substitute to make up for its mediocre Speed, as it is just fast enough to outspeed walls such as defensive Jirachi and Heatran, can make 101 HP Subtitutes and 2HKO Clefable, and Ice Shard threatens faster Pokemon weak to Ice enough to get it a free turn. Mamoswine also has an effective support movepool with options such as Knock Off and Stealth Rock.

Mamoswine unfortunately has a large list of problems in OU stemming from its lack of strong physical Ice-type moves, its mediocre Speed and the consequences of it, and a metagame very hostile to Ice-types. While Mamoswine has Ice Shard, its best physical Ice-type move otherwise is Ice Fang, which simply isn’t strong enough to threaten bulkier Pokemon immune to Ground such as Gyarados, Bronzong, Skarmory, Rotom-A, and Cresselia or even very bulky Pokemon weak to Ice such as Hippowdon, physically defensive Zapdos, and Celebi. Mamoswine has to rely on Blizzard in hail and its bad base 70 Special Attack to threaten these Pokemon. Mamoswine’s stats give it a conundrum, as its base 80 Speed stat forces heavy investment lest it get outsped by most of the metagame. However, its base 110 HP stat needs a lot of investment to reach 101 HP Substitutes, and Mamoswine always wants more power. Mamoswine is forced into this conundrum because of how hostile DPP OU is to its typing. Mamoswine has extremely common weaknesses to Steel, Fighting, Fire, and Water, and Grass while it is only immune to Electric and resistant to Poison. No amount of investment into Mamoswine’s defenses will save it from Jirachi, Scizor, Bronzong, Lucario, Infernape, Gyarados, Suicune, Swampert, Starmie, Heatran, Breloom, Machamp, and the huge amount of Pokemon with super effective coverage such as Tyranitar, Gengar, Latias, and Zapdos who all either can outspeed it or live one hit and remove it. On top of this, Mamoswine is grounded and despises poison, paralysis, and burn, making it easier to pick off. These flaws make Mamoswine niche in DPP OU, on the cusp of excellence but held back from being a staple of the tier.