UU Hazard Stack.

Forretress @ Leftovers
Ability: Sturdy
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Spikes
- Rapid Spin
- Toxic
- Volt Switch

Gyarados @ Leftovers
Ability: Intimidate
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Substitute
- Dragon Dance
- Waterfall
- Bounce

Swampert-Mega @ Swampertite
Ability: Damp
EVs: 72 HP / 252 Atk / 4 SpD / 180 Spe
- Waterfall
- Rain Dance
- Ice Punch
- Earthquake

Chandelure @ Choice Specs
Ability: Flash Fire
EVs: 252 SpA / 252 Spe
Modest Nature
IVs: 0 Atk
- Shadow Ball
- Fire Blast
- Trick
- Memento

Conkeldurr @ Leftovers
Ability: Guts
EVs: 240 HP / 16 Atk / 252 SpD
Adamant Nature
- Bulk Up
- Drain Punch
- Knock Off
- Mach Punch

Metagross @ Leftovers
Ability: Clear Body
EVs: 204 HP / 36 Atk / 92 SpD / 176 Spe
Adamant Nature
- Stealth Rock
- Zen Headbutt
- Meteor Mash
- Bullet Punch