Metallica is a group.
Metallica is an American heavy metal band based in San Rafael , California . Guitarist Dave Mustaine ( who went on to form rivals Megadeth ) and bassists Ron McGovney , Cliff Burton and Jason Newsted are former members of the band . The band 's fast tempos , instrumentals , and aggressive musicianship placed them as one of the founding `` big four '' bands of thrash metal , alongside Megadeth , Anthrax and Slayer .