Froslass/Dragonite Snow Offense

Synergy

Mega Froslass sets Snow on evolving for a free Aurora Veil, Alolan Ninetales backs that up while also carrying a surprise Rain Dance specifically to neutralize opposing Mega Charizard, and Mega Dragonite has an extremely positive matchup into that same Charizard once Rain is up.

Win Conditions

Double Aurora Veil from Ninetales and Froslass buys the bulk for Basculegion and Kingambit to grind through a game, while the Ninetales into Dragonite Rain Dance line and Frost Breath's guaranteed crit are built specifically to blow up Mega Charizard and Mega Staraptor before they can act.

Lead Options

Ninetales-Alola + Dragonite, Basculegion + Ninetales-Alola

Threats

The team runs Protect on almost nothing but Basculegion, so it's vulnerable to opposing Fake Out, though Mega Froslass itself can't be hit by Fake Out at all. The video also notes this build is tuned more for best-of-one play, so it loses some surprise value once an opponent has already seen it.