Going into Toronto, speculation about Marielle Heller’s “Nightbitch” had reached a fever pitch. Would the film, adapted from Rachel Yoder’s novel of the same name, be the vehicle to win Amy Adams an Oscar after six fruitless nominations? Or would it be a misguided, tonally jarring hot mess with a title to inspire a thousand dog puns? “Nightbitch” works largely thanks to Adams’ nimble, fearless performance as an artist-turned-stay-at-home mom who puts her once-promising career on hold to care for her cute but rambunctious toddler. (Her character, never named, is listed in the credits as “Mother.”) Her well-meaning but clueless husband, played by Scoot McNair, frequently travels for work, leaving her at home to fend for herself and whip up countless pots of macaroni and cheese. Exhausted and resentful, she begins to notice bizarre physical changes — a heightened sense of smell, a patch of fur on her back. “Nightbitch” is a surreal, insightful film about the joys and anguish of motherhood and the sometimes disturbing ways that becoming a parent can transform women’s minds, bodies, emotional lives and entire sense of self. It won’t be for everyone, but neither is being a parent. — Blake