Mastodon is among the new breed of American metal bands that appeals to fans of extreme metal, while combining elements of progressive music and beyond. After a successful stint on Relapse Records, the band jumped to Warner Brothers for its 2006 release "Blood Mountain" and its new release "Crack the Skye." The album reaches even further into sonic exploration without sacrificing any of the thunderous immensity of previous releases. It may offend some of the death-metal conservatives, but it will likely rope in an even larger audience. Five days after tonight's performance, Mastodon will be performing at Coachella.