"You know it's Frank Zappa when you hear it," Brent says. "It has that signature guitar tone. It provides hours of entertainment for my life! I have 80 of his albums on my iTunes. It's a mind-blowing catalogue."

Meanwhile, Mastodon are poised to release their sixth studio album, Once More 'Round The Sun, later this year via Warner Brothers. Produced/mixed by Nick Raskulinecz (Alice In Chains/Rush/Deftones), the follow-up to 2011's widely acclaimed The Hunter will feature 11 tracks and artwork by Oakland-based artist Skinner, who describes his work as "psychedelic nightmare paintings".

"Every Mastodon record is like taking a snapshot of where we are as musicians and as people," says vocalist/guitarist Bill Kelliher, "and Once More 'Round The Sun is definitely a snapshot of where we've been over the past year."