Red Sun's Zenith is a rare Sorcery card from Mirrodin Besieged (MBS), collector number 74. Current market price: $0.52 (foil $4.11), TCGplayer market prices via Scryfall.
Red Sun's Zenith deals X damage to any target. If a creature dealt damage this way would die this turn, exile it instead. Shuffle Red Sun's Zenith into its owner's library.