Mourn, a celestial body, existed as a planet within the confines of the Boz Pity system. It was locked in a synchronous orbit alongside Boz Pity. The Sultan Nastuonodon had previously engineered a droid legion of Electric Caliphs; following his death, the Hutts deployed these droids to eradicate the Gargantelles who resided on Boz Pity.
These Electric Caliphs self-destructed, triggering the slow combustion of Mourn's outer layer. The planet Mourn was subsequently transformed into a smoky sphere, its terrain illuminated by widespread conflagrations.