Battle Pike team 2.0

The team:

G (Gengar) (G) @ Cleanse Tag
Ability: Levitate
Level: 50
EVs: 212 Atk / 116 SpA / 180 Spe
Mild nature
IVs: 31 HP / 31 Atk / 31 Def / 31 SpA / 31 SpD / 31 Spe
- Psychic
- Thunderbolt
- Ice Punch
- Explosion

H (Heracross) (F) @ Choice Band
Ability: Guts
Level: 50
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant nature
IVs: 31 HP / 31 Atk / 31 Def / 31 SpA / 31 SpD / 31 Spe
- Megahorn
- Brick Break
- Facade
- Earthquake

L (Latios) @ Lum Berry
Ability: Levitate
Level: 50
EVs: 4 HP / 252 SpA / 252 Spe
Modest nature
IVs: 31 HP / 0 Atk / 31 Def / 31 SpA / 31 SpD / 31 Spe
- Psychic
- Thunderbolt
- Surf
- Dragon Claw

Notes:
- Double battles can't appear if you have 1 Pokemon left. So if you get an early double battle, explode with Gengar for a quick win that also prevents future double battles. The Cleanse Tag still works even if Gengar is fainted.
- Heracross is ridiculously powerful with Guts + Facade + poison/burn from one of the status rooms.