Nasty Baby is amiably aimless, until its ruinous final act

Reportedly, Silva—a Chilean-born filmmaker whose previous features include The Maid and Crystal Fairy—wrote a 20-page outline rather than a screenplay, encouraging the cast to improvise most of the dialogue. Until the movie abruptly derails in the third act, everyone except Silva himself (who’s never before played a role of this magnitude onscreen) does a creditable job. There’s none of the repetitive flailing and dead air that permeates Joe Swanberg’s recent improv exercises (Digging For Fire, Happy Christmas)—these characters relate to each other like longtime friends and lovers, not like actors struggling to think of something to say. Wiig, in particular, turns in a relaxed, natural performance that’s neither expressly funny nor self-consciously dour, which have been her two primary modes to date. And while the baby-making storyline feels a tad inconsequential—Mo’s brief second thoughts about serving as a sperm donor is the only real conflict, speedily resolved—it’s refreshing to see material like this treated as if it’s no big deal.

Just when the film is starting to feel too aimless, however, it’s trainwreck time. First, Silva returns to the “Nasty Baby” project, expanded in idiocy (it now involves Freddy, Polly, Mo, and a friend played by Alia Shawkat pretending to be squalling infants, though none of them gets naked) and trumped by a gallery owner’s batshit-crazy response to it. But that’s nothing compared to the sudden swerve that brings Cathey’s neighborhood lunatic front and center. What had been a light, cozy comedy—short on laughs, but with ample warmth and affection—abruptly metamorphoses into a preposterous thriller, as a minor act of violence snowballs into behavior that qualifies as downright evil. This gearshift neither emerges organically from the skeletal narrative nor thematically dovetails with the other storylines in any way. It’s just a Hail Mary attempt to prevent the movie from flatlining, reeking of desperation and retroactively tainting everything that precedes it. At long last, Nasty Baby decides what it wants to be: a complete mess.

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