In a dismal manner; in a way that is gloomy, depressing, or miserably.
From dismal + -ly (adverbial suffix). This is a standard formation turning the adjective into an adverb to describe how something is done or appears.
When something goes 'dismally wrong' rather than just 'wrong,' the adverb adds emotional weight—it's not just failure, it's failure wrapped in gloom and despair.
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