Big Thief have invented a scary, fanciful musical world. The Brooklyn folk-rock band’s two 2019 albums — U.F.O.F., out since May, and Two Hands, out since October — invent an imagined environment with its own internal logic, a densely wooded forest with strange, benevolent creatures lurking in the shadows, hidden machinery creaking under the soil. They also rock, providing a reassuring touch of familiarity.

Big Thief have been crafting fragile, noisy rock miniatures since their debut, Masterpiece (2016), on which their warm, rustic sound first emerged in a more rickety, lo-fi context. Thanks to the band’s collective confidence and increasing willingness to pursue weirdness, on the two new albums that sound becomes its own striking, fully developed sonic template. These songs flicker, keyed to the intricate chitchat between Buck Meek’s acoustic and electric guitars, which entwine with a hushed lightness accentuated and often obliterated by blasts of electric noise that eventually subside. Adrianne Lenker’s quavery, bent singing matches this aesthetic vocally. Thus they achieve a skewed balance between energy and calm, a quietly declarative introspection.

Since not many folk-rock bands now sound like anything new, Big Thief stand out — their attraction to the genre comes not from rote traditionalism or the desire to embrace confessional tropes and let hearts bleed on sleeves, but from a fondness for whimsy. They love American folk music for its vivid surreality, for the way vernacular idioms and stories with holes in them can create mystery; they aim to capture the surprise of listening to an old song that talks to you directly from another place. Of their rock predecessors, they rather remind me of early R.E.M., whose strummed jangle and verbal inscrutability similarly conjured an immersive, half-remembered pastoral Southern dreamworld. Big Thief’s dreamworld is wilder, with many songs set in the natural wilderness, but it has the same enigmatic allure.

Of their two 2019 albums, U.F.O.F. is quieter, given to tiny plucked guitar arpeggios that emerge as hooks through the haze. After a few listens, each song rings out with disconcerting familiarity, like discovering a clearing in the woods you know you’ve been to before but can’t place when. The lyrics bristle with nature imagery: meteor showers, loons among the cattails, fruit bats crying, birds eating worms, silkworms boiled to make thread (“Strange”), frozen pigeons hitting the ground (“Orange”), dogs barking in the distance. It’s too spooky to count as pastoral; U.F.O.F. has a musty quality, a faint smell of mothballs.

“Cattails” marches grandly, threading a circular guitar figure through a wall of stark strumming. The verses move through a rapid series of tangentially related images that hint at death or rebirth, but Lenker always returns to the clear, simple refrain: “You don’t need to know why when you cry.” “Contact” opens the album on a haunting note: for three minutes, Lenker sings in a ghostly whisper as a cautious, jangly riff builds tension; then, there’s suddenly a bloodcurdling scream, like a canned horror sound effect, and the guitars explode, as she and Meek tear gashes in the song’s fabric. The screams continue for the rest of it; although the ending note lands with a chill, it also resolves the song’s melody.

Two Hands is tighter and punchier, with an earthy mix of guitar crackle and twang. These songs exist in the same knotty world and wander on the same back roads but sometimes achieve meaning more directly. Lyrically, the focus has shifted from animals to human bodies, as Lenker fills the songs with eerie, detached descriptions of blood and teeth, mangled by wolves. “Forgotten Eyes” is almost a standard rock anthem, complete with rousing melody and slogan (“Everybody needs a home and deserves protection”); the sunny acoustic riff gleams over darker, crunchier chords.

The album peaks with “Not,” a condensed six-minute epic divided roughly into a sung half and a guitar-solo half. By repeatedly negating different things (“It’s not the room/not beginning/not the crowd/not winning/not the planet/not spinning,” and so on) without specifying what she’s referring to, before launching into a raw, furious, agitated guitar eruption, almost straining to get the notes out, she captures a basic, total yearning and implies that yearning is too fundamental to express in words.

Despite Big Thief’s immersion in folk-rock convention, these are not easy albums to listen to. The wispy grain of Lenker’s voice and the sepia-tinged guitar sound can repel. Often her lyrics revel in a sort of physical grotesqueness, aiming for bodily horror — for example, her descriptions of bruises and blood, and lines like “I can hear her flesh crying little rivers in her forearm,” as well as the bugs and dirt everywhere, the swarming moths in the window. U.F.O.F. and Two Hands churn the stomach much in the manner of the giant insects in Miyazaki’s Nausicaa of the Valley of the Wind; both use revulsion as a distancing device, a way of emphasizing strangeness and ultimately inspiring awe at a system that is beautiful and alien. Lenker’s calm, forlorn singing, conveying wonder, is crucial in this regard, and it’s unclear if she’s an outsider in the dreamworld or a human foil, or whether she belongs here.

There’s often an underlying erotic subtext, as is conventional in the pastoral; many of the forest scenes could also be scenes of intimacy, especially given moments of gender ambiguity (“It’s not the boy I’m seeing, with her long black hair,” she sings on “Not”) and songs that clearly, if obliquely, describe romantic relationships between women (“Orange”). As with many contemporary depictions of nature under climate change’s shadow, there’s also a desperation to this music, an underlying sense that something fragile is threatened, made more ominous by the partial conflation of nature with the erotic. Both albums depict wild spaces, of whatever sort, worth treasuring because they’re endangered.

That these songs are made possible by technological modulation — the disruptive presence of electric guitars, say — is their defining contradiction, perhaps the source of their strange power. Moments of joy and surprise abound too — especially on U.F.O.F.’s “Jenni,” an enraptured exhalation of guitar static and breathy delight, with few lyrics besides “Jenni’s in my room,” which Lenker repeats again and again, as if trying to believe it. Lost in the noise, the guitar fuzz, the emotion, this is the sound of a swoon.

U.F.O.F. and Two Hands are beautiful and painful albums, animated by an emotional rawness that’s rare in folk music. By using conventional musical forms to illuminate a weird new sensibility, they achieve an unsettling combination of comfort and surprise. Steeped in shadows and electricity, they rock out and keep their secrets.