What is Undertale?

Apple Bloom just stares at the pile of photos beside her then looks back at the camera.
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Apple Bloom: "Anyway....we now go live ta Sweetie Belle who is interviewin' Silver Spoon about.... Undertale? Alrighty then."
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Cuts to Sweetie Belle.
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Sweetie Belle: "Thank you Apple Bloom! I'm here at the pathway with Silver Spoon and Diamond Tiara.
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Diamond Tiara: "Silvy, you do the interview, I'm gonna check out that fence over there."
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Silver Spoon: "Uhm,ok Di."
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Sweetie Belle: "Hi Silver Spoon!"
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Silver Spoon: "Hello."