Primarina's Whirlpool-plus-Perish Song combo traps and forcibly removes the opponent as the team's core "Perish trap," while Mega Metagross pushes through with honest, unboosted power even without Clear Body's stat-immunity edge mattering much. Hippowdon clears the front with Sandstorm and Stealth Rock. Once the trap lands, the team can play the rest of the game with a numbers advantage, which is especially effective against stall.
Primarina (Leftovers, Torrent): Surf / Perish Song / Whirlpool / Protect. A trapping support that binds the opponent with Whirlpool and forces it out with Perish Song.
Mega Metagross (Clear Body): Meteor Mash / Hammer Arm / Grass Knot / Bullet Punch. A physical pillar that ignores stat drops thanks to Clear Body and finishes with Bullet Punch priority.
Mimikyu (Life Orb, Disguise): Play Rough / Shadow Claw / Shadow Sneak / Swords Dance. Doubles its power with Swords Dance before landing the finishing blow with Shadow Sneak priority.
Hippowdon (Sitrus Berry, Sand Stream): Earthquake / Stealth Rock / Slack Off / Whirlwind. Provides both Sandstorm and Stealth Rock at once, and Whirlwind doubles as an answer to Trick Room and stat-up sweepers.
Charizard (Blaze): Overheat / Solar Beam / Flamethrower / Ancient Power. Handles the special damage line, hoping Ancient Power's random boost lands.
Garchomp (Focus Sash, Rough Skin)