Question: Who was the name of the bassist featured on  the American rock band Weezers most successful studio album?

<P0-S0> My Music is the third and most successful studio album by Bosnian alternative rock band Sikter. <P0-S1>  It was released on 21 August 2005 by Bosnian label Gramofon. <P0-S2>  Album was recorded from 2003 to 2005 at MML Studio in Sarajevo and mixed at MGKS Studio in Sarajevo 2005. <P0-S3>  Cover of album was made by bassist of the band Dragan Rokvić. <SEP> <P1-S0>  The album was a huge commercial success, peaking at number 16 on the US "Billboard" 200 and spawning the singles "Undone – The Sweater Song" and "Buddy Holly", both of which were responsible for launching Weezer into mainstream success with the aid of music videos directed by Spike Jonze. <P1-S1>  It has sold 3.3 million copies in the United States and has been certified triple platinum by the Recording Industry Association of America (RIAA), becoming the band's best selling album to date. <P1-S2>  Following the success of their debut album, Weezer took a break from touring for the Christmas holidays. <P1-S3>  Lead singer Rivers Cuomo began piecing together demo material for Weezer's second studio album. <P1-S4>  Cuomo's original concept for the album was a space-themed rock opera, "Songs from the Black Hole". <P1-S5>  Ultimately, the "Songs from the Black Hole" album concept was dropped; the band, however, continued to utilize songs from these sessions into work for their second studio album. " <P1-S6> The discography of Weezer, an American rock band, consists of 10 studio albums, two compilation albums, one video album, six extended plays, twenty-eight singles and twenty-four music videos. Weezer's self-titled debut studio album, often referred to as "The Blue Album", was released in May 1994 through DGC Records. <P1-S7> Pinkerton" was released as the band's second studio album in September 1996. <P1-S8>  Peaking at number 19 on the "Billboard" 200, it was considered a critical and commercial failure at the time of its release, selling far less than its triple platinum predecessor. <P1-S9>  However, in the years following its release, it has seen much critical and commercial championing. <SEP> <P2-S0> Black Sabbath were an English hard rock band from Aston, Birmingham. <P2-S1>  Formed in 1968, the group originally featured vocalist Ozzy Osbourne, guitarist Tony Iommi, bassist Geezer Butler and drummer Bill Ward. <P2-S2>  The initial lineup of the band lasted until 1977, during which time they released seven successful studio albums, including UK Albums Chart top-five releases "Paranoid", "Master of Reality" and "Sabbath Bloody Sabbath". <P2-S3>  Osbourne left the group in 1977 and was replaced briefly by Dave Walker, although the founding frontman returned the following year. <P2-S4>  His return was short-lived, however, and he was replaced in 1979 by Ronnie James Dio at the suggestion of Sharon Arden, who would later marry Osbourne. <P2-S5>  Butler also briefly left in 1979, although after hearing sessions recorded by replacement Craig Gruber he returned. <SEP> <P3-S0> Pinkerton is the second studio album by American rock band Weezer, released on September 24, 1996 on DGC Records. <P3-S1>  After abandoning plans for a rock opera titled "Songs from the Black Hole", Weezer recorded "Pinkerton" between songwriter Rivers Cuomo's terms at Harvard University, where he wrote much of the album. <P3-S2>  It was the last Weezer album to feature bassist Matt Sharp.