Nannie Doss, often dubbed the "Giggling Granny," was an American woman whose charming demeanor belied a shocking reality: she was a notorious serial killer. Born in 1905 in Alabama, Doss killed her four husbands, two children, and several other relatives, often using poison. Her unsettling laughter and friendly appearance stood in stark contrast to her heinous actions, which were mainly motivated by a desire for financial gain and independence.