This contribution examines the changing representation of mothers in Opera from the eighteenth to the nineteenth century. It argues that the deliberate absence of mothers in early opera, exemplified by Metastasio's works, gave way to their reemergence as evil figures in later periods. Through three case studies—Handel's Agrippina, Mozart's Die Zauberflöte, and Donizetti's Lucrezia Borgia—this study contends that this transformation reflects broader societal changes, brought about by the French Revolution and the rise of bourgeois family models. It explores how operatic mothers embody tensions between maternal love and power, often manifesting in themes of incest or redemption through sacrifice. The analysis highlights the gendered aspects of operatic roles, the influence of literary sources, and the musical techniques used to represent maternal characters. By tracing the journey from absence to monstrosity, this contribution offers insights into how opera has grappled with the figure of the monstrous mother, reflecting and shaping different attitudes towards motherhood, power, and morality.