After making the leap from indie to major, the Atlanta-based metal band Mastodon release their long-awaited third album Blood Mountain. Not many bands have the skill to evolve and encapsulate an entire ideology of metal from one album to the next. The first two Mastodon records—2002’s Remission and 2004’s Leviathan—were thunderous and venomous, while Blood Mountain seems to have a little more groove. It’s still heavy enough to rip paint from the walls, but it’s just not as ominous. It’s...