Who knows what the hell a “burl” is or why it would “curl?” We certainly don’t, but that’s not what’s important here. What’s important is that Atlanta metal kings Mastodon have released the second song, titled -- you guessed it -- ‘Curl of the Burl,’ from their fifth studio album, ‘The Hunter,’ which hits stores Sept. 27.

‘Curl of the Burl’ offers a more tangible approach to the typically hard-hitting, prog-intensive Mastodon extravaganza. And that makes sense, considering ‘The Hunter’ was helmed by Mike Elizondo, the internationally renowned mega-producer behind some of the biggest hits from people like Eminem, 50 Cent, Alanis Morissette and Blake Shelton. In other words, people who normally wouldn't touch Mastodon with a 10-foot pole.

Elizondo knows a hook when he hears one -- even when it’s hidden in a thick sonic stew of sludge rock, as Mastodon have been known to do. On ‘Curl,’ he finds his hook in a chorus of “Oh oh, oh ohs” and builds off that, letting the band’s precise shredding act as a conduit to the big payoff. The result is a song that could easily fit in between Queens of the Stone Age and Alice in Chains on your radio and not sound the least bit out of place.

Mastodon are that rare breed of metal band that everybody seems to love. They can certainly hold their own opening for Metallica on a trans-Euro tour, then go rock out in front of a mass of geeked-out hipsters at the Pitchfork festival and still shine. Dave Grohl likes them so much he had them back up the Foo Fighters on an epic version of Led Zeppelin's 'Kashmir' at the 2007 MTV Video Awards. Honestly, the Foos had never rocked so hard.

And with ‘Curl of the Burl,’ Mastodon sound a little more like Foo Fighters. They certainly rock out, but center things around a hook that would make Grohl proud.

Now, if we could just figure out what those lyrics mean . . .

Listen to Mastodon, 'Curl of the Burl'