Shieldon and Bastiodon are two fossil creatures available for capture in Pokémon Legends: Arceus. Taking place in the ancient past of the Sinnoh region, Pokémon Legends: Arceus is all about exploring the surroundings and completing the Pokédex. Outside of just capturing Pokémon, trainers are tasked with feeding them, defeating them in specific ways, or just spending quality time with them. In the case of Sheldon and Bastiodon, in Pokémon Diamond and Pearl, this Pokémon needed to be resurrected with the proper fossil. They are fairly powerful Rock and Steel-type Pokémon that trainers will need to capture to complete the game.
Clearing out the game will not only reward trainers with the Shiny Charm item but also always them to face off against the Deity Pokémon itself. If trainers are able to successfully capture every Pokémon in the Hisui region, they'll be able to take on this secret boss. Although, Shieldon and Bastiodon are not Pokémon that appear naturally when exploring the wilds. Trainers will need to wait until they have access to Coronet Highlands before they can hunt for these fossil Pokémon.
Related: Pokémon Legends: Arceus — Traces Of A Lost Village Request Guide
Shieldon and Bastiodon have the chance to appear inside of Space-Time Distortions exclusively in Coronet Highlands. After defeating the Noble Pokémon, Kleavor, these will randomly appear around the map and in-game text notifications will appear when they are forming. The best thing to do would be to explore the area and complete any remaining tasks to kill time. Space-Time Distortions appear when they want to but can provide players with a chance to find rare items and Pokémon. Both Shieldon and Bastiodon can be captured separately inside of these
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