In 1997, Phish were jamming in a studio in Woodstock. Sequestered from the world, the quartet improvised for hours with the goal of finding some exciting bits to refine and embellish for its next studio album. Most of the material wound up on The Story of the Ghost, a funky, brittle album released just before Halloween the next year. But there was still some good stuff left over, so keyboardist Page McConnell took it upon himself to edit and compile it into a brief instrumental companion. They called it The Siket Disc, named after recording engineer John Siket, and released it directly to fans on their website in June 1999. An official release came via Elektra in November 2000. Only one song ever became a regular in their live sets, but the music found another purpose on tour, soundtracking the band’s late-night drives in the van.

As far as facts go, that’s all there is to it. There are nine jams, totaling just over 35 minutes altogether, culled from a period many fans recognize as the band’s prime. If The Siket Disc simply offered the best of those jams—distinguished as “Type I” when they’re following a song’s general chord progression or “Type II” when they veer into spacier territory—it would likely still have something worth recommending. But something strange happened during these sessions in Woodstock. Distinct even from The Story of the Ghost, The Siket Disc is unlike anything in Phish’s catalog. Compared to the buoyant highs they typically sought, these haunted, twilit valleys could feel like a photo negative of the band. It is the type of outlying statement that happens either with intense focus and vision or by accident: things the tape can’t help but capture.

From their moments of blissful transcendence to their goofiest in-jokes, you get the sense that, if Phish knew where any of their ideas were leading, they would have no interest in pursuing them. Like a good first date, their music aims for a natural rhythm, making each step feel somehow easy and inevitable while still advancing the action. When he formed the band in 1983, guitarist Trey Anastasio blended this impulse with conceptual songwriting and intricate, theatrical music—cerebral gestures that drew influence from oddball iconoclasts like Frank Zappa and bookish prog bands like Genesis. As the band quickly carved out a distinct voice, he loosened up, and even his virtuosic guitar playing became a tool for unity. “I feel like I’m there to be an intermediary between music that’s in the universe and the audience,” he told Guitar World in 1996. “It sounds silly, but I believe it more than I believe anything else in my life.”

That last sentence, as it happens, could be affixed to any of Phish’s work in the 15 years leading up to The Siket Disc. While conventional wisdom (and reams of music criticism) might suggest otherwise, they had already covered quite a lot of ground as a studio act, and they worked hard to differentiate their official discography from the scratchy bootleg tapes that catalyzed their loyal following. Among its entries was a set of dazzlingly weird compositions played live in the studio (1989’s Junta), a moody concept album that upped their emotional stakes (1993’s Rift), a brash rock album tailor-made for alternative radio (1994’s Hoist), and a tasteful, rootsy album that helped win over the jam skeptics (1996’s Billy Breathes).

During their formative gigs for fellow college students in Vermont, the appeal of a Phish show was all about what happens next—where any given song might take them, what new tricks they might reveal, what would happen when other scenes discover this wild, ecstatic music. Like so many gifted kids chasing their passion, the band’s boundless potential seemed to spur them on—even if the members seemed more interested in making each other laugh than singing in key or writing anything that might appeal to radio. As OG Phish head Tom Baggott recalls in Parke Puterbaugh’s Phish: The Biography, “It was like there was a big joke going on and all the early Phish fans knew the punchline—which was that this was gonna be something big.”

Here is the dream of every small-town weirdo, as played out on the stages of the music industry: One day you will step to the front of the classroom and dazzle everyone, from the snobby cool kids to the stuffy professors who never thought you had it in you. And once you’ve won them over, there’s no one left to please but yourself. With Phish, this posture was written so conclusively into their ascent that the trappings of mainstream success had little bearing on them. The major-label studio albums, no matter the effort and money behind them, would never hold fans’ attention like the cherished bootleg tapes. And even as they started selling out storied halls like Madison Square Garden in 1994, they had their sights set elsewhere: specifically, five miles north in Plattsburgh, New York, where they launched their own two-day festival that became the largest North American concert of 1996.

It’s an enviable place for any band—creating your own standards for success and finding an audience to achieve them with you—but it’s also dangerous territory. It’s one thing for the underdog to rise to the top of the class; it’s another thing to have to run the school. These concerns informed Anastasio’s 1988 college thesis, a heavily mythologized rock opera called The Man Who Stepped Into Yesterday. The plot, if I’m understanding it right (and I’m not sure I ever have), involves a utopian society called Gamehendge that becomes corrupted by power, then overthrown by a revolutionary, then eventually corrupted once again by that same revolutionary after he steps into power. Breaking onto the jam scene at a time when some heads saw the Grateful Dead in danger of burning and/or selling out, Anasatsio understood that good intentions and high ideals could only get you so far before real life starts to intrude.

Phish were feeling the pressure as they worked on The Story of the Ghost in 1997. Hoping to write more meaningful material to suit their new popularity, Anastasio arrived to the sessions with several songs he had co-written with lyricist Tom Marshall. His bandmates felt somewhat stifled by this idea. For one, because they had tried it before: hitting the studio with a batch of pre-written songs, only to watch them really take shape on the road. Secondly, this process seemed to reject the communal spirit that brought them together in the first place. Were they really just going to become Trey’s backing band? Was he now… a frontman? Had we learned nothing from Gamehendge?

And so, they settled on a more comfortable method of jamming endlessly, searching for songs, and ensuring that, just like their stage lineup, no member of Phish would stand in front of the others. This is how The Story of the Ghost winds up being something of a disappointment—to Anastasio at least. The band was playing at its best; each member had a say in the direction; nobody got in each other’s way. And this was exactly the problem. “The Story of the Ghost was our democratic album, our socialist album; if anyone didn’t like a song it was out,” Anasatasio reflected to Guitar.com. “But what happens with that approach is the material gets watered down.” By the next record, 2000’s Farmhouse, they returned to the previous approach, lost some of their spark, and made it back onto the album chart. Go figure.

Still, there were lessons to be learned. Part of The Siket Disc was inspired by a question someone asked Anastasio while at a Pavement show: “So how come every time you guys put an album out you do everything except what you do well?” It seems only natural that, if you’re a band whose best moments arrive unplanned, you would find a creative process that channels the same chemistry. Accordingly, the strongest Phish studio albums, from the nascent playfulness of Junta to the lived-in hum of Sigma Oasis, seem to invite us in on the fun. These are records that make room for patient exploration and willfully irritating zaniness; music that might take a master’s degree to annotate, with lyrics that could be written by middle schoolers goofing off in science class (and sometimes were).

I would argue this precise set of contradictions is what defines Phish to this day, what allowed them to evolve over the span of 40 years from an eccentric regional jam band to a classic rock institution. In oblique ways, these qualities are also what make The Siket Disc so fascinating, both an anomaly and an ideal gateway for new fans. The same way that someone put off by the gravelly triumph and saxed-up drama of the E Street Band might find sanctuary in the stark transmissions of Nebraska, I imagine even the most ardent skeptic could find moments of beauty on The Siket Disc—or at least admit, all right, that was a pretty cool guitar lick and at no point did I beg you to please make it stop.

All of this is without the magic trick that Phish typically reserves for their instrumental jams. It’s the moment that Amanda Petrusich has described as the climax of so many Phish shows, when the jam hits the double digits and the music seems to sweep us away: “a short but delightful vacation from my corporeal self,” as she writes. Throughout The Siket Disc, Phish avoid these cosmic escapes, either by laying into nervous repetition as on “Insects” or incorporating eerie silence into “The Name Is Slick,” where you can almost see the members picking up their instruments, gazing around the room, and seeking reassurance that they’re on the right track.

This type of trepidation was new for Phish, and I have sometimes heard it as an expression of the creeping anxieties that would eventually lead to their hiatus in 2004. You can sense this shift throughout Todd Phillips’ 2000 documentary, Bittersweet Motel, which depicts their growing strain and bleary-eyed time out of mind on the road. In one memorable scene, Anastasio goes on a brief rant about bad reviews and unfavorable comparisons to the Dead. As a means of distinguishing his own perspective—“In eighth grade, I was in New Jersey, going to the mall, and listening to what was on at the mall”—he ends up making a case for his band’s rightful place in the food chain. “The suburban white kid is part of history, whether you like it or not,” he declares. If so much of Phish’s music demonstrated the very suburban instinct to rebel and explore and laugh off the shackles of mundanity, then The Siket Disc was surrender. When they closed their eyes and let their minds wander, these were the landscapes they saw: slow, still, circling the same familiar cul-de-sacs.

Even within its limited range, The Siket Disc exposes a different side of the band. They frequently abandon all signifiers of their traditional sound, as in the noise collage of “Fish Bass,” or rearrange familiar parts to find new dynamics, like the heavenly guitar-and-bass duet of “Albert.” You could attribute these shifts to McConnell’s role as producer—he is a jazz aficionado, and there are times when the group seems to be channeling Miles Davis on his ambient jazz fusion record, In a Silent Way—or the fragmented nature of the recordings themselves. Many of the songs sit within the boundaries of one resounding chord, each member tugging to loosen its shape or finding ghostly overtones to cast around it. More often than not, the band seems to be attempting to imitate the sound of sputtering car wheels stuck in the snow.

The centerpiece, and the song they’ve returned to the most on stage, is “What’s the Use.” I would hail it as the most beautiful in-studio Phish performance, using each second of its 11:20 runtime to communicate a single emotion. From the moment it rises like a plane taking off from a sleepy runway to the steady fadeout into tape hiss, I’m not sure any song has so specifically conjured the feeling of pressing onward through exhaustion. In the decades since its release, The Siket Disc is the only Phish record to appropriately assume the genre descriptors of post-rock and ambient, and this song shows you how it might slot alongside contemporaneous releases from Thrill Jockey or Kranky.

“What’s the Use” requires each band member to make it land: John Fishman’s heavenly, waltz-time drumbeat; Gordon’s crystalline bassline; McConnell’s descending lullaby of a keyboard refrain, reserved for maximum impact just after the seven-minute mark. And yet, it also features the sole moment on the record that belongs exclusively to Anastasio. His extraordinary guitar solo seems to span the entire track, ascending the fretboard, never dissolving into pure noise but always in danger of being enveloped by feedback. As he reaches the highest note, he signals the rest of the band to cool off. It feels little like a cry for help, a distant siren fading in the night.

“Often there is a moment when it feels like the safety rails fall off,” Anastasio told The New Yorker of his favorite jams. “We lose any sense of time passing. Then I feel safe letting people see how I actually feel, which is terrified a lot of the time.” After all these years, it makes sense he feels most comfortable expressing this vulnerability in the adrenaline-fueled, communal peaks of a rock show. Sometimes I think about those peaks as literal heights, places we can only reach with the momentum and confidence that comes when a lot of people are gathered together, aiming our sights at the same slow-forming horizon. If that’s what you’re looking for in art, then Phish has made plenty of music to take you there. But this time, they were just four musicians in a studio, trying to write an album, taking momentary comfort in the lonesome, weary sound of going nowhere.