The first project outside of BLACK SABBATH that bassist Geezer Butler to find a release was the 1995 G//Z/R band. Butler had ventured out of the BLACK SABBATH confines previously in the 80's with various acts. The GEEZER BUTLER BAND of 1985 included guitarist Pedro Howse, vocalist Richie Callison, a native of St. Louis, Missouri (and subsequently to front HEAD EAST), and drummer John Mee. Former PERSIAN RISK vocalist Carl Sentence (later of erstwhile UFO guitarist PAUL CHAPMAN's GHOST and Swiss veterans KROKUS) also operated with Butler. A later line-up had ex-BIRD OF PREY vocalist Kyle Michaels fronting the band, later of MASI. Former WISHBONE ASH and TRAPEZE vocalist Mervyn Spence had been approached but declined.

Sallying back and forth between BLACK SABBATH in the 80's and 90's Butler, a member of OZZY OSBOURNE's band at the time, forged an extremely heavy proposition in 1995. Joining in were FEAR FACTORY vocalist Burton C. Bell. G//Z/R also comprised Bell's fellow American Deen Castronovo (formerly with such diverse acts as WILD DOGS, BAD ENGLISH and HARDLINE) was also part of OZZY OSBOURNE's rhythm section at the time of the album's release.

For the second album, 'Black Science', Bell had opted out due to commitments with FEAR FACTORY. Butler had changed the name of the band to GEEZER for the record's release, then simply GZR for a 2005 outing 'Ohmwork'. In 2005 Pedro Howse featured a guest guitar solo on ex-BLACK SABBATH singer TONY MARTIN's solo album 'Scream', appearing on the track 'Bitter Sweet'.