Answer by taking a quote from the following article:

Gorillaz are an English virtual band created in 1998 by musician Damon Albarn and artist Jamie Hewlett. The band consists of four animated members: 2-D (lead vocals, keyboards), Murdoc Niccals (bass guitar), Noodle (guitar, keyboards), and Russel Hobbs (drums and percussion). These members are fictional and are not personas of any "real life" musicians involved in the project. Their fictional universe is explored through the band's music videos, as well as a number of other short cartoons.

Musician Damon Albarn and comic book artist Jamie Hewlett met in 1990 when guitarist Graham Coxon, a fan of Hewlett's work, asked him to interview Blur, a band Albarn and Coxon had recently formed. The interview was published in Deadline magazine, home of Hewlett's comic strip Tank Girl. Hewlett initially thought Albarn was "arsey, a wanker"; despite becoming acquaintances with the band, they often did not get on, especially after Hewlett began seeing Coxon's ex-girlfriend Jane Olliver. Despite this, Albarn and Hewlett started sharing a flat on Westbourne Grove in London in 1997. Hewlett had recently broken up with Olliver and Albarn was at the end of his highly publicised relationship with Justine Frischmann of Elastica.  The idea to create Gorillaz came about when Albarn and Hewlett were watching MTV. Hewlett said, "If you watch MTV for too long, it's a bit like hell - there's nothing of substance there. So we got this idea for a cartoon band, something that would be a comment on that." The band originally identified themselves as "Gorilla" and the first song they recorded was "Ghost Train" which was later released as a B-side on their single "Rock the House" and the B-side compilation G Sides. The musicians behind Gorillaz' first incarnation included Albarn, Del the Funky Homosapien, Dan the Automator and Kid Koala, who had previously worked together on the track "Time Keeps on Slipping" for Deltron 3030's eponymous debut album.  Although not released under the Gorillaz name, Albarn has said that "one of the first ever Gorillaz tunes" was Blur's 1997 single "On Your Own", which was released for their fifth studio album Blur.

Did they have any other music?
first song they recorded was "Ghost Train" which was later released as a B-side on their single "Rock the House" and the B-side compilation G Sides.