Golgothian Sylex
The Golgothian Sylex was a mysterious ancient artifact, described as a large bowl made of a copper-like metal with curious glyphs on it, which roughly translate as "Use to wipe the world clean, to topple the empires, to start again".
The sylex was discovered by Feldon in the Ronom glacier during the Brothers' War. When Terisia City was besieged by Mishra's forces, Feldon entrusted the relic to Loran. Ashnod captured Loran, and passed the sylex through Tawnos to Urza, on Argoth, where Urza activated the device. The ensuing Sylex Blast destroyed both Urza's and Mishra's armies, altered Dominaria's climate to begin the Ice Age, and caused the downfall of most of Dominaria's major civilizations.
Long after the Brothers' War, the planeswalker Ravidel obtained the Golgothian Sylex through a bargain after a duel with Ash Warlord Embereck in a sunken city of Terisiare after the Ice Age. In Year One by the Reckoning of the Sages of Minorad, Ravidel appeared at Minorad and threatened to use the Sylex unless the five planeswalkers present—Liana of Minorad, Ash Warlord Embereck, Kristina of the Woods, Grenfell Mor of Golthonor and Altair of Coloni – promised not to interfere with his actions on Dominaria, to which they agreed. In the year 1281 by the Reckoning of the Sages of Minorad, Ravidel threatened to use it again, so Jared Carthalion and Kristina found the long-daggers that would destroy the Sylex. Jared used the daggers to make the Sylex vulnerable to a shatter spell, which finally destroyed the artifact.