Mamoswine

Mamoswine is a great wallbreaker in BDSP OU due to its excellent STAB combination and an insane Attack stat that makes it nearly unwallable. It makes great use of Life Orb, as its huge Attack stat and unique Ice-type priority move in Ice Shard allow it to finish off Dragon-types and can also be useful for chipping down neutral targets into KO range for other attacks. It can also make use of Substitute to ease prediction, with the drawback of less damage output. Unfortunately, while Mamoswine's typing is advantageous offensively, it's lacking defensively with no defensive utility outside of Thick Fat and an Electric immunity. Mamoswine is unable to capitalize off of this, as it can't consistently come in on Volt Switch from common Electric-types such as Rotom-W, while fellow Ground-type wallbreaker Garchomp can. Mamoswine's STAB moves, while good, can easily be played around. Combined with a mediocre Speed stat, this makes Mamoswine very prediction-reliant without Substitute compared to other, more reliable wallbreakers such as Crawdaunt, Azumarill, Infernape, Garchomp, and Breloom. Mamoswine's weaknesses also leave it vulnerable to common priority such as Aqua Jet, Mach Punch, and Bullet Punch from Crawdaunt, Azumarill, Infernape, and Scizor. Mamoswine also has great competition in the form of Garchomp, as the latter is often used over Mamoswine because of its higher consistency and better defenses. However, although Mamoswine possesses a great deal of weaknesses, its strength more than makes up for the effort needed, as Mamoswine's STAB combination makes switching into it effectively very tough, as most switch-ins get 2HKOed.