After only a minute, I was violently allergic. That singing - ouch. I felt as if an old friend had showed up in a shiny new Hummer. Something had changed irreparably.

Actually, I had seen it coming. Crack the Skye (Reprise, 2009) is the next logical step in Mastodon's evolution from metal band to prog band. The last few records had increasing amounts of singing and progginess. I could take it less and less; this one tipped the balance. Like Enslaved on Vertebrae, Mastodon finally dove headfirst into the lake of prog. Goodbye, riffs; hello, everything else.

Crack the Skye is a marvel of overkill - 1000 harmonies, 1000 layers, 1000 bucks an hour production. Mastodon have a way with melodies, and these are some of their catchiest tunes. Sad, then, that they desperately need Ritalin. Brann Dailor is no help; he has an awesomely dexterous inability to keep a pulse. This record is expensive and jittery. It could say something meaningful if only it settled the fuck down. This may be music to like or to appreciate. But if anyone claims an emotional connection to it, he is a liar.

Live is another story. In concert, Mastodon turn the tedious into the towering through sheer force of personality. This is how they've become America's most important - though far from the most potent - metal band. They are now the gateway into metal for many. It could be a lot worse (e.g., nu-metal, metalcore). Mastodon take worthy bands like Kylesa and Intronaut out on the road. They're probably the same dudes they've always been. Musically, though, I have to wish them goodbye and good luck.

- Cosmo Lee