Volcarona + Mega Gyarados

Volcarona @ Leftovers
Ability: Flame Body
EVs: 236 HP / 136 Def / 124 Spe
Bold Nature
- Fiery Dance
- Roost
- Bug Buzz
- Quiver Dance

Latias (F) @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Draco Meteor
- Psyshock
- Defog
- Healing Wish

Gyarados @ Gyaradosite
Ability: Intimidate
EVs: 4 HP / 252 Atk / 252 Spe
Adamant Nature
- Waterfall
- Earthquake
- Crunch
- Dragon Dance

Mew @ Leftovers
Ability: Synchronize
EVs: 252 HP / 96 Def / 160 Spe
Impish Nature
- Knock Off
- Taunt
- Will-O-Wisp
- Soft-Boiled

Garchomp @ Rocky Helmet
Ability: Rough Skin
EVs: 252 HP / 160 Def / 96 Spe
Impish Nature
- Stealth Rock
- Dragon Tail
- Earthquake
- Fire Blast

Scizor @ Choice Band
Ability: Technician
EVs: 208 HP / 252 Atk / 48 Spe
Adamant Nature
- Bullet Punch
- Superpower
- Knock Off
- U-turn