The only Bong Joon Ho I’d watched was “Snowpiercer,” a dystopian sci-fi extravaganza that left its mark on me, so I approached “Parasite” with respectful caution. Quite rightly, for this is a movie of passions and plots and themes writ large. A scrabbling family of four, residing in a Korean “sub-basement,” worms its way into a wealthy family’s house and existence. Dread builds and then, when you least expect it, the plot spirals in a new lurid direction, and then in another, and then in another, followed by a phantasmagoric Seoul street scene, followed by a sequence of short, telling redux scenes. The direction and cinematography are lockstep precise, the music wonderfully grandiose or menacing. The acting often feels unobtrusive, as if you are watching real people, with Cho Yeo-jeong outstanding as the naif rich wife. “Parasite” is a rush of plot tropes that leaves you scrambling to unpack the strong themes of class and jungle evolution and hopelessness and longing. A stunning film that, for once, offers what literature might not be able to offer.