Pancake hits the nail on the head.
Which is why I'm nominating a Bulky Stealth Rocker Alolan Marowak. Handles threats like Tapu Koko, provides Stealth Rock, and has good offensive presence to boot (along with spreading Wisp to cripple things like Landorus-T).
Marowak-Alola @ Thick Club
Ability: Lightning Rod
EVs: 248 HP / 96 Atk / 86 SpD / 68 Spe
Careful Nature
- Shadow Bone
- Fire Punch
- Will-O-Wisp
- Stealth Rock
EVs are a bit specific: Speed EVs outspeed minus speed Celesteela (most commonly Sassy), 96 Atk means you hit the same Atk as the 16 Atk Adamant spread (which is generally the minimum Atk you want) and still hit damn hard (80% min with Shadow Bone to Mega Metagross, putting it in guaranteed KO range of Specs Normal Greninja's Water Shuriken). Max HP + 86 SpD and a boosting nature means Standard Volcarona can't 2HKO with HP Ground or OHKO with it at +2 (while Shadow Bone does 78% minimum), and Specs Lele Modest Moonblast is a 3HKO. Even with 0 Defense investment, you eat an Earthquake from Mega Metagross and live (37.5% chance to be OHKO'd after Rocks), and you still take U-Turns with ease.
Moves are fairly standard: Wisp to cripple common switch ins like Garchomp and Lando-T, as well as neutering almost all physical attackers, Shadow Bone for powerful STAB that lets you 2HKO Heatran and most anything that doesn't resist or have huge defensive investment, Fire Punch over Flare Blitz because you really don't want recoil damage, and Stealth Rocks over Bonemerang because we need something to set Rocks, and Bonemerang targets like Heatran are already handled by the team.
