[2] After releasing only one album on a major label, Black Elvis/Lost in Space, Kool Keith subsequently returned to independently releasing music, producing further efforts as a solo artist and in collaboration with groups such as Analog Brothers, Masters of Illusion, Thee Undatakerz and Project Polaroid.

The Prodigy's hit "Smack My Bitch Up" was based on a sample of Kool Keith's voice saying "Change my pitch up.

[5] Ultramagnetic MCs would release two more albums (1992's Funk Your Head Up and 1993's The Four Horsemen) with little commercial success due to West Coast hip hop's changing landscape.

The album's production by Dan the Automator and Kutmasta Kurt, with scratching by DJ Qbert was acclaimed by critics, and the album was released nationally by DreamWorks Records in 1997, after an initial release on the smaller Bulk Recordings label (as, simply, Dr. Octagon) a year prior.

[3][4] In 1996, Thornton collaborated with Tim Dog for the single "The Industry is Wack", performing under the name Ultra[3][4]—the album Big Time soon followed.

Being a dirty rap concept album, Thornton described it as "pornocore", filled with sexual metaphors to diss other rappers.

The same year, on August 10, 1999, Thornton released Black Elvis/Lost in Space, under the major record labels Ruffhouse and Columbia.

It peaked at #10 on the Billboard Heatseekers chart, #74 on the Top R&B/Hip-Hop Albums chart, and #180 on the Billboard 200,[9] Despite standing out as Thornton's most commercially successful project to date, he was disappointed with the album's delays and promotional efforts, even though a promotional video was made for the lead single, "Livin' Astro", which aired on a few episodes of the MTV show Amp in early 2000.

[12] The following month, Thornton collaborated with Ice-T, Marc Live, Black Silver and Pimp Rex for the album Pimp to Eat, under the group name Analog Brothers, with Keith performing as Keith Korg and Ice-T as Ice Oscillator.

Thornton, Marc Live and H-Bomb formed the group KHM, releasing the album Game on November 19, 2002.

[4] During the same year (2004) that Clayborne Family was released in, Kool Keith Presents Thee Undatakerz (with Reverend Tom (Kool Keith) Al Bury-U (BIG NONAME), M-Balmer and The Funeral Director) and Diesel Truckers, another collaboration with KutMasta Kurt.

[16] On June 27, The Return of Dr. Octagon was released by OCD International, an imprint of CMH, advertised as the official follow-up to Dr.

Throughout five years, Thornton released Controller of Trap, Keith, Computer Technology, Saks 5th Ave, Space Goretex (with Thetan), Keith's Salon, Subatomic (with Del the Funky Homosapien), Serpent (with Real Bad Man), and Black Elvis 2.

Thornton's lyrics are often abstract,[30] surreal,[31] and filled with non-sequiturs, extreme violence, exaggerated braggadocio, and profane shock humor.

[32] For example, "Technical Difficulties," from the album Dr. Octagonecologyst contains the following lyrics: "Intestines, investments, hide money in your stomach / Who can stop Pepto-Bismol?

In "Extravagant Traveler" from Matthew, he boasts: "Sautéed fish and shrimp / the Dallas Mavericks want me as a bald-headed five-foot-eight guard with a ninety-five inch vertical / Vince Carter respects my legs, ask Shawn Kemp," whereas on "Miami Mike" from Saks Fifth Avenue he proclaims "I watch you take a shower in my 747 flying over your house / I used to live in the Twin Towers by myself."

As of 2012, Kool Keith had at least 58 such alter egos: these include well-known aliases such as Dr. Octagon, Dr. Dooom, and Black Elvis, which appeared on albums bearing their names; and the more obscure, such as firearms dealer "Crazy Lou" and "Exotron Geiger Counter One Gamma Plus Sequencer," as he introduced himself in an appearance on Marley Marl's radio show In Control.