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Great Desert (from Clown after breaking all rocks in the west section of the desert)

Sandstorm creates a tempestuous sandstorm lasting 5 turns and inflicts these effects: All Pokémon, except Ground, Rock, and Steel types, and those with the Magic Guard, Overcoat, Sand Force, Sand Rush, or Sand Veil abilities, lose 1/16 of their max HP per turn. From Generation 4 onwards, Rock-type Pokémon's Special Defense rises by 50%. Shore Up restores 2/3 of the user's max HP. Solar Beam and Solar Blade power diminishes by 50%. Synthesis, Morning Sun, and Moonlight recover 1/4 of the user's max HP. Weather Ball transforms into a Rock-type move with doubled power. Pokémon with Sand Force boost Rock, Ground, and Steel type moves by 30%. Pokémon with Sand Rush double their speed, while those with Sand Veil gain a 20% evasion increase.