Primordial Undermind, a project launched in 1993 by psychedelic singer and guitarist Eric Arn, formerly in Crystallized Movements and also in Outsideinside. was truly itinerant, as Arn moved from Boston to Los Angeles to Stanford to Austin.

The album Yet More Wonders Of The Invisible World (September Gurls, 1995), especially Temporal Landscape, introduced an ebullient garage-rock band inspired by Thirteenth Floor Elevator and Seeds rather than by more cerebral acid-rockers.

The singles Aenestethic Reveletations (Dionysus) and Ache/ Walk Me Home (Penultimate, 1996) proved the band's talent in skinning melodies and chopping riffs. Relying on the dual guitar phrasing of Arn and Brian Craft, You And Me And The Continuum (Camera Obscura, 1998) opened up to a spacier sound. The slow-burning, 9-minute Device merges elements of the Grateful Dead's Dark Star and the Pink Floyd's Astronomy Domine. Turning Of The Worm emerges from a bacchanal of Hendrix-ian glissandos. The funereal litany of Persistence of Trinity ends in a concerto of dissonances. Ache, All Night Movie and Aenesthetic Revelations are dirty, messy ballads in the tradition of Television and Dream Syndicate, albeit penalized by poor recording quality.
However, the band can still pack a significant punch, as in the terrifying Now I Wanna Take A Bath, an MC5-grade rock and roll. Bassist David Stankoski contributes Scenic Horrors, a noisy and anthemic orgy a` la Velvet Underground.

Having replaced the rhythm section and added Doug Pearson on violin and keyboards, Universe I've Got (Camera Obscura, 1999) turns on the amps and jams freer than ever in Hawkwind's land. The better recording certainly helps deliver the concept. The point is carried home especially by the galloping raga Hypomorphic Array and by the turbo-charged space guitars of the nine-minute Manta. The even longer Weightless Nemesis soars via epic riffs at martial pace, echoing the most metaphysical moments of Neil Young's career, and the longest of them all, Dervish, pays homage to the middle-eastern tradition that inspires so much of PU's music. Its stratospheric crescendo is punctuated by a baroque architecture of swirls and waves.
On the other hand, the hypnotic guitar patterns and whispered mantra of Bandhu leave behind an almost gothic atmosphere when they disappear and are replaced by a crowd of whistling synths. And the lowest point is reached by the dilated trip of Jean To Sloan, hardly a song at all.

Beings Of Game P-U (Camera Obscura, 2001), that features new guitarist Tom Carter (Mike Gunn, Charalambides), Travis Weller on violin and keyboards, and drummer Jared Barron, is Arn's first Texan album. The style has changed considerably, and now presents similarities with free-form space-rockers such as Bardo Pond. The quartet's speciality are now lengthy all-instrumental jams (six of them on this album). The proceedings open with the 15-minute Uva Urtana, awash in languid Indian wails, interstellar drones, rhythmic black holes, and eventually fading away in deep space. Glass/Spitt/Revelation abandons pure bliss to delve into a hypnotic boogie punctuated by Hendrix-ian guitars. Louse Dances For Laos weaves more raga tones, cosmic frequencies and delirious guitar distortions. Melody surfaces only in Filament, a transcendent psalm refracted by the guitar against a distorted rainbow. Liquid Facets wraps up the album with a concert of ambient drones and eerie echoes, slowly fading into a dilated space of sparse sounds.

Thin Shells of Revolution (Emperor Jones, 2003) opens with a demented pseudo-Satriani instrumental, Flaming Lizard Inauguration, that Eric Arn's space guitar propels to the status of epics. That "trip" resumes with Ten Toes One Soul, which returns to Primordial Undermind's classical style. Otis Cleveland's flute adds a Jethro Tull-ish feeling to the jamming in Wwoo, which is otherwise jazzier than most. But most of the tracks sound like leftovers from previous projects, or ideas barely sketched. Half of the album is taken up by covers, clearly not a good sign (despite how the band mauls the Dead Kennedy's Kinky Sex). While the talent is still palpable, there isn't enough substance to call it an "album".

Loss of Affect (Strange Attractors, 2006) meant, first and foremost, a loss of inspiration. Each piece starts with an intriguing premise but fails to materialize the concept. The album as a whole sounds like a continuous coitus interruptus, whether it's delving into acid-rock jams or cosmic tapestries or brainy prog-rock structures.