In South Sudan, the rumor that the Murle people suffer from infertility evolved into a politically instrumental myth used to justify child abduction, securitization, and systemic exclusion. Rooted in colonial misrepresentations, the claim pathologizes Murle reproduction and legitimizes violence. Drawing on ethnography and archival, medical, and humanitarian sources, the article conceptualizes this narrative as a rumor-myth: a necropolitical discourse that transforms speculation into governance. Though lacking evidence, the infertility narrative endures through repetition and political utility. Counter-oral histories challenge these racialized fictions, revealing how communities contest exclusion and expose the broader structures of power that sustain scapegoating, violence, and inequality.