Mastodon: Blood Mountain

Let's settle something first: Blood Mountain is the metal album of the year. And with all its mangled complexity, extreme style changes and crazed time signatures, it's also the year's best prog-rock album. Sorry, Mars Volta.

But best of all, Blood Mountain is one of the overall albums of the year.

However, the problem with a demanding release like this is whether a wider audience is prepared to give it a go. In this case it's a challenge worth taking.

Right from the panic-stricken first beats of The Wolf Is Loose it's an unsettling, difficult and tense beast. But that's what makes it so interesting - a trait that's hard to come by in much of today's metal. So turn it up, devour it and you won't be disappointed.

The Atlanta quartet's second album, Leviathan, from 2004, inspired wider interest in the band thanks to songs like Blood and Thunder and Iron Tusk, which had a brutality as well as killer hooks.

On that album, the ravaging and muscular vocals made it a daunting listen, but on Blood Mountain they are more varied and palatable.

Sleeping Giant is downright beautiful as it dreamily awakens, with romantic harmonics coming in, and then stirring, deep, groaning vocals. But that's the only lovely moment here, so don't get used to it.

The rest is challenging, tough, and lethal. Songs like Circle Of Cysquatch, Bladecatcher and the savage Capillarian Crest veer into directions that are deluded and disturbing.

Then there's the three songs with guest spots: first, the clinical rage of Crystal Skull (with Scott Kelly from Neurosis); then the testy Siberian Divide (featuring Mars Volta's Cedric Bixler-Zavala); and finally Colony Of Birchmen (with Josh Homme from Queens of the Stone Age), a bludgeoning, stoned metal masterpiece.

Crikey, it's enough to give you sharp goosebumps.

Blood Mountain is Mastodon's first album for major record label subsidiary Reprise, but don't think they've sold out like many doubters predicted. Their loyalty and affiliation to boundary-pushing record label Relapse remains.

Similar to Tool and System Of A Down, this is extreme music with the power to be popular. But really, the challenge is yours to get in there and revel in it.

Label: Reprise/Relapse