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Frostbite added into the mainline games after not being in Gen 9
>Ice type version of Will-o-Wisp created that inflicts Frostbite
>Non-Ice types can only inflict Frostbite with Ice type moves
>Ice types using moves that inflict Frostbite (barring the status move from earlier) inflict Freeze instead
Also:
>Increase distribution of Slush Rush
>Ice now resists Water, but Scald is super effective on Ice types like Freeze Dry is on Water types
>Scald is redistributed to more Pokemon, base power lowered to 70 to compensate