Gyarados @ Choice Specs  
Ability: Intimidate  
EVs: 252 SpA / 4 SpD / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Hydro Pump  
- Hurricane  
- Thunder  
- Fire Blast  

Pelipper @ Damp Rock  
Ability: Drizzle  
EVs: 248 HP / 252 Def / 8 SpD  
Bold Nature  
- Defog  
- Scald  
- U-turn  
- Roost  

Swampert-Mega @ Swampertite  
Ability: Swift Swim  
EVs: 252 Atk / 4 SpD / 252 Spe  
Adamant Nature  
- Waterfall  
- Earthquake  
- Ice Punch  
- Stealth Rock  

Tapu Koko @ Electrium Z  
Ability: Electric Surge  
EVs: 200 Atk / 56 SpA / 252 Spe  
Naive Nature  
- Wild Charge  
- Brave Bird  
- U-turn  
- Hidden Power [Ice]  

Serperior @ Meadow Plate  
Ability: Contrary  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Glare  
- Leaf Storm  
- Dragon Pulse  
- Hidden Power [Electric]  

Tornadus @ Focus Sash  
Ability: Prankster  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
- Hurricane  
- Focus Blast  
- U-turn  
- Rain Dance