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Sheoldred's Terror

Instant

Destroy target creature not originally printed in an Argentum expansion. (Mirrodin, Darksteel, Fifth Dawn, Scars of Mirrodin, Mirrodin Besieged, New Phyrexia, and Phyrexia: All Will Be One are Argentum expansions. Argentum is Karn's original name for that plane, now you know!)