Trick Room.

Camerupt-Mega @ Cameruptite
Ability: Sheer Force
EVs: 4 HP / 252 Atk / 252 SpA
Quiet Nature
IVs: 0 Spe
- Fire Blast
- Earth Power
- Stone Edge
- Explosion

Aromatisse @ Leftovers
Ability: Aroma Veil
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Spe
- Wish
- Trick Room
- Moonblast
- Aromatherapy

Porygon2 @ Eviolite
Ability: Download
EVs: 252 HP / 192 SpA / 64 SpD
Quiet Nature
IVs: 0 Spe
- Thunderbolt
- Ice Beam
- Recover
- Trick Room

Slowbro @ Leftovers
Ability: Regenerator
EVs: 252 HP / 8 Def / 248 SpA
Quiet Nature
IVs: 0 Spe
- Scald
- Fire Blast
- Psyshock
- Trick Room

Schadenfreude (Chesnaught) @ Life Orb
Ability: Bulletproof
EVs: 252 HP / 252 Atk / 4 SpD
Brave Nature
IVs: 0 Spe
- Drain Punch
- Wood Hammer
- Stone Edge
- Synthesis

Escavalier @ Assault Vest
Ability: Overcoat
EVs: 252 HP / 252 Atk / 4 SpD
Brave Nature
IVs: 0 Spe
- Megahorn
- Iron Head
- Drill Run
- Knock Off