Australian filmmaker Jennifer Kent was already in the headspace of her script about a mother exhausted by her disturbed young son when a Melbourne father hurled his 5-year-old daughter off a bridge. This, she thought grimly, was exactly what her movie wanted to explore: how a person — a parent — becomes a monster. Her 2014 breakout hit is named for its actual monster, a gangly, clattery creation that could have escaped from a German Expressionist horror film. Yet audiences were more shocked by Essie Davis and her harrowing performance as a single mom who can’t bear another minute of tending to her difficult child. William Friedkin claimed he’d never seen a more terrifying film. But some women told Kent it was comforting to see that they weren’t alone.