Darth Krayt's Galactic Empire used gravity mines instead of expensive interdictor ships to keep the major hyperspace lines blocked from both the Empire-in-exile and the Galactic Alliance Core Fleet. The gravity mines created mass shadows that pulled the ships into realspace and made them unable to jump again, but unlike large interdictors, they were much smaller and more difficult to detect with sensors. Also, there could be up to hundreds of mines spread across the area to create an overlapping larger mass shadow. Some more expensive mines could even magnetically attach itself to enemy starships, making them unable to be destroyed without outside assistance.
- Luke Skywalker and the Shadows of Mindor (First appearance)