A new Pokémon introduced in Pokémon Scarlet & Violet's DLC, The Indigo Disk, is the Steel-/Dragon-type Archaludon that you can find from the evolutionary path of another creature you catch. Archaludon evolves from Duraludon, but only when you use a specific item bought from a vendor. You have to complete several quests in the DLC to afford to get the right object.