Bonnarooing: Masto Blastos

We don't think Bonnaroo is turning into a hard rock festival anytime soon, but by golly if they didn't wind up booking both the most influential and still most popular metal band in the world (Metallica) and also the most promising relatively new act in the genre this weekend.

The latter would be, of course, Mastodon, who were absolutely jaw-dropping during their Saturday set. Moshing isn't usually part of the deal at Bonnaroo, but it was in full force during crushing rockers like "Crystal Skull" and "Crimson Rider," which used Metallica's harmonized guitar leads as a jumping-off point for exceedingly adventurous twists on the metal template.

There's just something about the riffs and stop-on-a-dime time changes these guys pull off that puts an enormous smile on our faces. We think they may have played at least one new song from the album they're making in Atlanta right now with producer Brendan O'Brien, but don't quote us on that.