Scarf Necrozma with T-Wave to punish Clef/Corv Switch and Toxic to punish Mandibuzz Switch+Scarf Necrozma Speedtie with Zera so we have Ferro for it+ Mandi for Ghosts+Terrakion for Dark Types+ Rotom for Clef

Necrozma @ Choice Scarf  
Ability: Prism Armor  
Shiny: Yes  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Photon Geyser  
- Heat Wave  
- Toxic  
- Thunder Wave

Ferrothorn @ Rocky Helmet  
Ability: Iron Barbs  
EVs: 248 HP / 252 Def / 8 SpD  
Impish Nature  
- Stealth Rock  
- Leech Seed  
- Knock Off  
- Body Press

Clefable @ Leftovers  
Ability: Magic Guard  
EVs: 252 HP / 4 Def / 252 SpD  
Calm Nature  
IVs: 0 Atk / 30 Spe  
- Wish  
- Protect  
- Teleport  
- Moonblast

Mandibuzz (F) @ Heavy-Duty Boots  
Ability: Overcoat  
EVs: 248 HP / 164 SpD / 96 Spe  
Careful Nature  
- Foul Play  
- U-turn  
- Roost  
- Defog

Rotom-Heat @ Heavy-Duty Boots  
Ability: Levitate  
EVs: 244 HP / 16 SpA / 248 Spe  
Timid Nature  
IVs: 0 Atk  
- Nasty Plot  
- Overheat  
- Volt Switch  
- Pain Split

Terrakion @ Choice Band  
Ability: Justified  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Stone Edge  
- Close Combat  
- Earthquake  
- Quick Attack