FYI: Dragon Fang Modest Draco Meteor from Hydreigon is a guaranteed OHKO on 252 HP Archaludon
Just sharing this because I have not seen anyone use it and I literally end up sniping Arch almost every game I play against it. Of course this is for a team that is just insanely Arch weak and needs a dark type. I do think there is some serious merit though, and no one is expecting.