In the realm of hyperspace, a mass shadow represented the gravitational imprint left by a substantial object residing in normal space. Due to the potentially lethal nature of these shadows to any starship venturing too close, it was imperative to prevent collisions by meticulously planning hyperspace jumps. The simulation of a celestial body's gravity shadow could lead to the termination of a ship's hyperspace journey or the prevention of a jump to hyperspace within an interdiction field.
During the Imperial Era, the primary star of the Throffdon system underwent a supernova event, resulting in the creation of mass shadows. While smuggler Han Solo was traveling towards Gwongdeen, his vessel, the Millennium Falcon, was forcibly extracted from hyperspace due to the mass shadows generated by the Throffdon star. Speculation arose that the Galactic Empire had engineered a superweapon known as the Mass Shadow Generator, capable of existing simultaneously in both space and hyperspace.
In an early glimpse of the novel The High Republic: Light of the Jedi, the Great Hyperspace Disaster of the High Republic Era commenced when the freighter Legacy Run unexpectedly encountered a mass shadow situated within a hyperspace lane. Despite the efforts of the freighter's captain, Hedda Casset, to steer the ship clear in the dwindling moments before impact, the Legacy Run collided with the obstruction at a glancing angle and was completely destroyed. The finalized edition of the 2021 novel retains these events; however, mentions of mass shadows are absent.