This is a stall/cycle build that dropped the Stealth Rock Garchomp axis, which kept getting pre-emptively knocked out by fast opponents, and instead made Hippowdon, which doesn't die easily early on, the new axis, pairing it with a Taunt-set Mega Gyarados. To cover Gyarados's weakness of drawing in Stealth Rock users, it adopted a Mimikyu with high matchup power, and for its cycle partner, an Archaludon with a critical-hit item build discovered from a broadcast.
Hippowdon+Gyarados+one more slot are the default picks; Archaludon is added when a cycle battle is expected, and Mimikyu when a pure matchup battle is expected. Hippowdon shifts its physical/special allocation depending on the opponent, handling both Yawn play and Stealth Rock deployment, while Gyarados uses Taunt to shut down Baton Pass/stacking strategies. The remaining two slots (Blaziken and Alolan Ninetales) are cards carried over unchanged from a previous build, and the author themselves admitted the reasoning for using them was comparatively weak.