Tear of Isha
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The Tear of Isha was a stellar manipulator. It was kept in the Omega Arsenal. The Tear was designed to collapse black holes. Rassilon ordered the use of the Tear on the Tantalus Eye, in order to prevent a Dalek plan to wipe Gallifrey from history so then they would win the war. This plan, and the use of the Tear, was prevented by the War Doctor, who travelled to the end of the universe. Cinder then fired the Tear into a red giant, collapsing the star. (PROSE: Engines of War)