Poison mono

Venusaur @ Venusaurite
Ability: Overgrow
EVs: 252 HP / 212 Def / 28 SpD / 16 Spe
Bold Nature
IVs: 0 Atk
- Sludge Bomb
- Synthesis
- Leech Seed
- Giga Drain

Toxapex @ Black Sludge
Ability: Regenerator
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Scald
- Recover
- Toxic Spikes
- Haze

Nihilego @ Choice Scarf
Ability: Beast Boost
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Power Gem
- Sludge Wave
- Hidden Power [Ice]
- Thunderbolt

Muk-Alola @ Assault Vest
Ability: Poison Touch
EVs: 248 HP / 12 Atk / 248 SpD
Careful Nature
- Gunk Shot
- Knock Off
- Pursuit
- Shadow Sneak

Crobat @ Black Sludge
Ability: Infiltrator
EVs: 248 HP / 8 SpD / 252 Spe
Jolly Nature
- Brave Bird
- Roost
- Defog
- U-turn

Nidoking @ Life Orb
Ability: Sheer Force
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Earth Power
- Sludge Wave
- Fire Blast
- Ice Beam