Mr Bungle has often been portrayed as a Mike Patton side-project. Arguably, that term was more applicable to Faith No More. Formed in San Francisco in 1985, Bungle predated Patton’s involvement with FNM by several years, and would outlive them, too. Those with a yen to watch it can even revel in footage of an adolescent Bungle performing in the Eureka High School talent contest. A few members would come and go over the years, but the original core - Patton, guitarist Trey Spruance and bassist Trevor Dunn - would remain together until Bungle eventually fizzled away in the early 2000s. The band had previously released four demos, but it was Patton’s rapid elevation to MTV superstardom that finally landed Mr Bungle a multi-album deal with a grasping but unsuspecting Warner Brothers in 1990. Indeed, the video for 'Epic' features Patton ungallantly promoting his other project in the memorable 'There's A Tractor In My Balls' t-shirt.

Produced by and with an uncredited guest appearance from avant-garde workhorse John Zorn, Mr Bungle's self-titled 1991 debut was a startlingly bizarre record then, and a riotous if slightly puerile one now. It's brash, fun, obscene and often deliberately annoying - starting with 30 seconds of silence just to confuse you, with between-song skits of shitting noises, porn and information film samples, barely discernible field recordings and Mantovani-syle muzak. However, for all their reliance on farts and boobies and cracking one off, the songs themselves are quite astonishing mishmashes of forward-charging metal, rambunctious ska, warped carnival music and completely indefinable weirdness. At times -'Travolta', 'Dead Goon', 'Love Is A Fist' - Bungle hone their silliness into something genuinely terrifying, essentially the homicidal clown trope in musical form. Hammering the point home with an oversized mallet, the album art is taken from Dave Loupare and Dan Sweetman's illustrated novella A Cotton Candy Autopsy, a Bradbury-meets-Bukowski tale of sex, violence, alcohol, death and surprising tenderness among a group of depraved circus clowns.

Mr Bungle found a niche audience among FNM fans, but left many others baffled, and the album was generally torn to pieces in the conservative metal press. Recording and touring Angel Dust - an album that saw more than a bit of Bungle's depravity creep into Faith No More's DNA - took up much of Patton's time over the next couple of years. It would be 1995 when their second album hit. And my, how they'd grown.

While the debut had elements of darkness and horror, the overall impression was bright and colourful, full of mischievous glee. Anyone expecting the same from Disco Volante (Italian for 'Flying Saucer') or for Bungle to follow up on FNM's commercial success, would be sorely disappointed. Warner Brothers in particular, one suspects, were dismayed by their contractual obligation to release this monstrosity. Opening track 'Everyone I Went To High School With Is Dead' is remarkable in its attempt to be deliberately off-putting - it has none of the malevolent buoyancy of the first album, just a crushing, despondently tuneless, repetitive, sludgy dirge with monotone yelling, passages of arrhythmic chaos and stuttering noise. It's less than three minutes, but seems much longer, and not necessarily in a good way. But it's deliberate. It's a test. If you can't cope with this, don't bother continuing. Go back to your shiny Faith No More records, civilian dilettantes. In 1995, FNM too were in their darkest and most wilfully repugnant period, with the bleak King For A Day and Patton sporting the world's worst moustache and revelling in a monsoon of sputum from a Chilean audience (as documented in some nauseating live footage). But none of that could compare with the sheer, lurching queasiness of DV's opening.

Ostensibly a stark contrast, 'Chemical Marriage' bounds in as soon as its predecessor collapses. It's a seemingly cheery and amiable jazzy bossa nova, yet there's a considerable undercurrent of mania to it. Sour harmonies counterpoint friendly chords, sounding both warmly accessible and profoundly unsettling. At the halfway point, clashing discordances hocket back and forth furiously, recalling the profane possession of the church organist in Carnival Of Souls.

The surreal, breakneck jazz of 'Carry Stress In The Jaw' follows, beginning with Dunn and Bär Mackinnon doubling wild bass and sax lines reminiscent of Dave Holland’s Conference Of The Birds. Eerie organs and spectral quotations of Edgar Allen Poe waft over a studiously constructed clatter, both intense and ambient. Unexpectedly, a passage of free-jazz segues seamlessly into vicious, razor-precise death metal, as if these two forms are natural bedfellows. More jazzy doubling follows, this time George Benson-as-serial-killer, as Patton's sleazy barroom 4AM crooner matches note-for-note Dunn's trills and runs, finally exploding into a grotesque metal-with-horns riff. It's an astounding genre mash, yet doesn't come off like someone pointlessly ramming together incompatible styles. It makes sense on its own terms.

Hidden from the tracklist but lurking between tracks three and four is the aptly named 'The Secret Song'. On the vinyl version, this was double-grooved - precise and fortuitous needle placement was required if you were to ever hear this song at all. A spy theme that never was, this jazzy, mathy take on the twangy Peter Gunn/Pink Panther template is bass-led, yet recorded without Trevor Dunn's knowledge. The Grampa Simpson-style vocals are Dunn recording himself complaining about his lack of involvement. It makes for one of the album's lightest, silliest, most instantly appealing tracks.

Echoing Trey Spruance's deepening fascination with Middle Eastern music (which would reach full, glorious expression in Secret Chiefs 3). 'Desert Search For Techno Allah' is similarly direct - a deliriously hard-pounding stomp, full of heavy beats, chanting and Arabian flourishes, slowing to a crawl for some climactic doomy guitars and portentous wailing. The title, however, is overly self-descriptive and blunt, one at which 21st-century Spruance, a keen student of Islamic mysticism and alchemical traditions, might well baulk.

'Violenza Domestica' more patchwork than song - a discombobulating array of sudden stabs, horror soundtrack swells and crescendos, clattering metal objects, and gothic European pop, with Patton crooning and whispering threateningly in Italian. It almost seems like a studio collage or an improvisation, until you see Bungle play it note-for-note live. This is perhaps the furthest point yet from the debut's puppy-boisterous, brattish ska-carnival-metal, a compositionally sophisticated, impressionistic piece, taking as much inspiration from Luciano Berio or from Zorn cut-up works such as Spillane and Godard as it does from Morricone's giallo work. The lyrical thrust, as far as one can deduce based on rudimentary Italian and the sonic storytelling, is as upsetting as you might surmise.

Both lyrically and musically, 'After School Special' feels like a companion piece. However, it's much simpler, almost hymnal or nursery rhyme-ish, though undercut by those same sour/lush chords that pervade everything. Often prioritising phonetics over meaning, Mike Patton is on unusually sensitive form, continuing the theme of domestic abuse, but here witnessed and experienced from the perspective of a child. Whether performed with the cynical smirk he's often accused of, or with genuine empathy, the line "Once Dad hit me so hard, Mom felt it on her cheek" has genuine power in this understated, innocuously sinister setting.

'Phlegmatics' bursts in, built from thrash drumming and huge slabs of discord, gearing up for an all-out metal onslaught, but then grinds to a halt. A section of repugnantly drowsy abstraction follows, sickening in its oily horror, as Patton croons, vaulting octaves with contrary slowness:

"Pulmonate gastropod

Oh, for insomnia!

Render me proficient

If not at least useful"

By contrast, 'Ma Meeshka Mow Skwoz' is just delightful - a giddy, impossibly fast cartoon romp straight out of Carl Stalling's wildest Tex Avery dreams, beefed up by cinema organs, surf guitar, flashes of metal and a clever, constantly mutating arrangement. Rollicking, instantly appealing and technically impressive, it's even proved oddly popular among high-school percussion ensembles.

Arguably the album's dark heart, 'The Bends' is a ten-minute, multi-part sound collage of jazz, musique concrète, primitive sci-fi electronica and looming horror soundtracks. If the album thus far seemed to be mastered a little on the quiet and muted side, the reason for this becomes apparent here - so that the into-the red noise section in this track SCARES THE LIVING FUCK OUT OF YOU. A whole album of extremely ambitious and difficult music, further hamstrung simply for the purpose of maximum terror an hour in. Disco Volante does not go out of its way to be liked.

Sandwiched between 'The Bends' and closer 'Merry Go Bye-Bye', 'Backstrokin' and 'Platypus' are perhaps the weakest moments, almost throwaways - the former, a brief diversion into deconstructed doo-wop and threatening lift music; the latter, a frankly incoherent mess of jazzy grooves, metal riffs and evil crooning, which feels like old-school Bungle, a rejected cut from the debut, left out for being too wilfully structureless and unmemorable.

Arguably, the best is saved for (almost) last. 'Merry Go Bye-Bye', the greatest Elvis song that never was, is a poignant meditation on mortality, played with surprising deftness and disarming frivolousness. For the most part, it's a light, jaunty, acoustic rock & roll/country number, aside from a three-minute diversion into totally foul and super-tight death metal - a seemingly unrelated but thematically appropriate digression. The lyrics, though obtuse, appear to speak of differing visions of the afterlife.

"Here to paradise they go

Brighter made is their woe

As above, so below.”

As the song's protagonist attempts suicide, conquering his fear of the hell conjured by the diabolical mid-section, either becoming reconciled to a heavenly vision or being convinced to spare his own life by the song's sumptuous, grandiose, Vegas cabaret finale. The excessive lounge bombast with which Bungle deliver the closing section could be taken as ironic gesture, but it's played completely straight, and heightens the emotional impact of the climax.

However, while 'Merry Go Bye-Bye' closes the album proper, it's not the end. Just to be extra confounding, there's a track called 'Nothing' that doesn't actually exist, followed by an untitled bonus track of rudimentary free improvisation.

Deliberately confrontational can be entertaining enough in the moment, but does that ethos endure, 25 years later? In 1995, there was nothing else like Disco Volante. And I don't think that situation has changed. Compositionally, sonically, in terms of atmosphere and feel, it still stands alone. The closest comparison, at least in terms of genre-jumping and sheer musicianship, is perhaps John Zorn's Naked City, but Disco Volante rejects Zorn's clean sonic palette and sense of chaotic joy for a repugnant, claustrophobic nightmare. The production job alone is extraordinary - at once grim and lo-fi, and yet capable of being sumptuous and sparkling, too. These moments of clarity and beauty reveal the underwater murk as a deliberate choice rather than a shortcoming. It complements the recurring trick of sweetness undercut by threat, of beauty shot through with an indefinable horror, to create something that feels like a thousand other musics smeared across a greasy window.

It's clear that Bungle are exceptional musicians, but the album is deliberately self-defeating. It takes the clichéd concept of 'the difficult second album' and turns that difficulty into its defining characteristic. It opens with a hostile dirge that conveys both nothing and everything about what is to follow. It covers itself with obscuring grease and grime. It tries its best to be unpredictable and evade comprehension. They have, in Mike Patton, one of the world's most adept and versatile vocalists, yet he's rarely at the forefront. His vocals are often woven in, acting as a textural element rather than a narrative tool or performance focus. In effect, if not in actuality, Disco Volante is largely instrumental.

Even at its prettiest, lightest, silliest and most fun, there's an undeniable menace to this record, a bottomless darkness that can be difficult to stomach. And yet, on occasion (especially 'After School Special' and 'Merry Go Bye-Bye'), Mr Bungle are able to take something extremely disorienting, nonsensical and wrong and coax some real, gut-churning emotion from it. The cognitive dissonance of this is hard to overstate - it's like a soulful Pixar moment in a David Lynch film. In fact, the David Lynch comparison is highly apt. Like Lynch, Bungle during this time period had a knack for taking vintage tropes from idealised visions of a more innocent time - for Lynch, mid-American suburbia, lounge singers; for Bungle, jazz, doo-wop, lounge singers - and making nightmares from them. The band's affinity for Lynch was made explicit on the self-titled debut, which featured several samples from Blue Velvet. However, if that album was a delightful Frank Booth party, Disco Volante is the entirety of Inland Empire - the creator's muse at its most unfettered, entirely unconcerned with convention or the audience's expectations, wrapped up completely in its own idiosyncratic, perverse and terrible dream-logic. They'd go on to one more record, full of actual, coherent, catchy and downright wonderful songs - the lush, Beach Boys-influenced California - but Disco Volante is Mr Bungle at their most Mr Bungle.

On a personal level, as intimated in a previous anniversary column that somewhat gave away the dénouement of this one, DV was the record that shattered my entirely metal-centric adolescent worldview. I approached it as a Faith No More fan, even a Mr Bungle fan, but it shook everything. It introduced me, in subtly terrifying ways, to the revolutionary idea that things unrelated to metal and hard rock could be worthwhile. Pre-1995, if it didn't have long hair and a Flying V, I basically wasn't interested. Soon after DV's release, I found myself tentatively exploring jazz and 20th-century classical, experimental and improvised music, eventually developing an affinity for easy listening, for electronic music, for noise, for soundtracks, for the Japanese underground, for non-Western traditions… for everything. While The Real Thing awakened my interest in music for the first time, Disco Volante pulverised all of my preconceptions about what music could and should be, and kicked me into an entirely new reality - one that 25 years on I've barely begun to explore.