This week Bruce speaks to Bill and Brann from massive metal band Mastodon. Having formed in 2000, Mastodon have succeeded in creating an innovative, category-defying blend of grindcore and growling death metal that has earned them significant critical acclaim. Having toured nearly non stop, the guys have additionally earned a reputation as an accessible and approachable band - and also secured a Grammy nomination for their album Blood Mountain. Guitarist Bill and drummer Brann will be telling Bruce all about working with super producer Brendan O'Brien and the mind boggling concept behind the new record. They also let us know how they're feeling about touring Europe this summer with Metallica.