Premise: Black Sabbath . The band experienced multiple line-up changes , with Iommi being the only constant member throughout its history . Originally formed as a blues rock band , the group soon adopted the Black Sabbath moniker and began incorporating occult themes with horror-inspired lyrics and tuned-down guitars . They were ranked by MTV as the `` Greatest Metal Band '' of all time , and placed second in VH1 's `` 100 Greatest Artists of Hard Rock '' list .
Hypothesis: Black Sabbath was a band.
Label: ENTAILMENT