Mamoswine @ Life Orb
Jolly/Adamant Nature
Ability: Thick Fat
EVs: 252 Atk / 4 SpD / 252 Spe
- Earthquake
- Ice Shard
- Icicle Crash
- Stealth Rock
It shouldn’t be too surprising that Mamoswine can put some work in OU despite being UU by usage. Those STABs don’t lie and with proper prediction it devastates the majority of the tier. This Ice-weak core is no exception.
Jolly is overall better but Adamant packs way more power. Outspeeds and OHKOs Zygarde with either nature, Tornadus-T can’t afford to switch in to Defog the rocks away, and Ice Shard has a 50% chance to OHKO Tornadus-T after rocks if it’s Jolly. Mamoswine can’t switch into either, but it pressures both to an extreme degree with its raw power and decent speed scaring Zygarde out pretty easily and then it can capitalize on those forced switches by either getting Stealth Rock up to put Torn-T into Ice Shard range when it comes in or just hitting hard as fuck with EQ predictions if a Steel wants to come in on Icicle Crash.