Groudon @ Red Orb  
Ability: Electric Surge  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Adamant Nature  
- V-create  
- Stealth Rock  
- Will-O-Wisp  
- Strength Sap  

Suicune @ Rocky Helmet  
Ability: Magic Bounce  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Jolly Nature  
- Anchor Shot  
- Spectral Thief  
- Entrainment  
- Heal Order  

Yveltal @ Toxic Orb  
Ability: Poison Heal  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Jolly Nature  
- Knock Off  
- Shift Gear  
- Will-O-Wisp  
- Rapid Spin  

Gengar-Mega @ Spooky Plate  
Ability: Mold Breaker  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Will-O-Wisp  
- Spikes  
- Sludge Bomb  
- Judgment  

Mewtwo-Mega-Y @ Toxic Orb  
Ability: Poison Heal  
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Psystrike  
- Moonblast  
- Earth Power  
- Taunt  

Aerodactyl-Mega @ Safety Goggles  
Ability: Prankster  
EVs: 252 HP / 252 Atk / 252 Def / 252 SpD / 252 Spe  
Jolly Nature  
- Haze  
- Head Smash  
- Shore Up  
- Nuzzle