The user will lose half of its maximum HP and put a curse on the target. A cursed Pokémon will lose ¼ of its maximum HP at the end of each turn; the user can use Curse if it has less than half of its maximum HP remaining, but will cause itself to faint. The curse will remain until the Pokémon switches out or the battle ends.
So if the opponent switches out, the Curse will no longer affect it.
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