Even if it weren't for the masks, Des Moines, Iowa's Slipknot would be one of metal's most terrifying propositions. Their platinum-selling, self-titled 1999 debut was a harrowing fusion of death metal and shout-along hardcore, but that was nothing compared to the sample-heavy screamscapes of later LPs—not to mention an explosive live show powered by adrenaline, pyro, and three drummers. In 2010, the death of founding member Paul Gray seemed to spell the end of the band, but the surviving members returned in 2014 with .5: The Gray Chapter in tribute to their fallen bassist.