CosseTeam (it's terrible)

Latios @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 1 Atk / 30 SpA / 30 SpD
- Psyshock
- Draco Meteor
- Hidden Power [Ground]
- Protect

Charizard-Mega-Y @ Charizardite Y
Ability: Blaze
EVs: 128 HP / 64 Def / 168 SpA / 148 Spe
Timid Nature
IVs: 0 Atk
- Heat Wave
- Solar Beam
- Overheat
- Protect

Swampert @ Expert Belt
Ability: Torrent
EVs: 252 HP / 252 SpA / 4 SpD
Modest Nature
IVs: 0 Atk
- Earth Power
- Ice Beam
- Scald
- Wide Guard

Thundurus @ Sitrus Berry
Ability: Prankster
EVs: 248 HP / 164 Def / 4 SpA / 72 SpD / 20 Spe
Modest Nature
IVs: 0 Atk / 30 Def
- Thunderbolt
- Hidden Power [Ice]
- Thunder Wave
- Taunt

Venusaur @ Life Orb
Ability: Chlorophyll
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
IVs: 0 Atk
- Giga Drain
- Sludge Bomb
- Sleep Powder
- Protect

Bisharp @ Focus Sash
Ability: Defiant
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Sucker Punch
- Knock Off
- Iron Head
- Protect