The early 2000s film industry leaned hard into the mother-in-law as a primal force of nature. Monster-in-Law (2005) starring Jane Fonda and Jennifer Lopez, literalized the title. Fonda’s character, a legendary newscaster, uses psychological warfare, sabotage, and even biological warfare (an allergic reaction to a cat) to destroy her son’s engagement. It was cartoonish, but it spoke to a real fear: that a mother’s love, when threatened by a daughter-in-law, can curdle into obsession.