This team's concept is the double-bind of Mega Raichu-Y and Mega Gengar (using its real Shadow Tag). Raichu-Y is equipped with Electric/Fighting moves that never miss, plus a Grass-type move to check Ground types, making it so the opponent can't casually bring in a Ground type or a Choice Scarf check as a follow-up; adding Mega Gengar, which uses genuine Shadow Tag, on top of this distorts the opponent's entire cycle. The Garchomp that Raichu-Y lures in is split up and handled by three Pokémon: Orthworm, Hippowdon, and Primarina.
The basic cycle is to use Raichu-Y to narrow down the opponent's safe switch-ins, then respond with Orthworm, Hippowdon, or Primarina when Garchomp comes out, building momentum with Orthworm's critical-point pivot move or Hippowdon's Yawn, and finishing with Primarina or Hippowdon. Against opponents difficult to break through with the cycle, the team forcibly creates a winning position using Mega Gengar's Shadow Tag + self-sacrificing move, and the pivoting power of Choice Scarf Hydreigon.