Kartana @ Focus Sash  
Ability: Huge Power  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Adamant Nature  
- Shell Smash  
- Sunsteel Strike  
- Searing Sunraze Smash  
- Ice Shard  

Gyarados @ Gyaradosite  
Ability: Wonder Guard  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Adamant Nature  
- Shell Smash  
- Power Trip  
- Substitute  
- Ice Shard  

Steelix-Mega @ Safety Goggles  
Ability: Prankster  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Impish Nature  
- Stealth Rock  
- Haze  
- Thousand Waves  
- Soft-Boiled  

Rayquaza-Mega @ Leftovers  
Ability: Triage  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Tail Glow  
- Oblivion Wing  
- Moongeist Beam  
- Draining Kiss  

Gengar-Mega @ Choice Scarf  
Ability: Parental Bond  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Trick  
- Moongeist Beam  
- Sludge Wave  
- Bug Buzz  

Arceus @ Safety Goggles  
Ability: Wonder Guard  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD  
Relaxed Nature  
IVs: 0 Atk / 0 Spe  
- Defog  
- Core Enforcer  
- Slack Off  
- Parting Shot