Based on his videos and interviews, Dave Grohl clearly knows a thing or two about humor, which surely helped him stay sane in the wake of Kurt Cobain's suicide. He also knows more than a few things about hard rock, particularly speed, thrash, and death metal. Probot finds Grohl pounding out headbanger beats and riffs as a cauldron of underground-metal roarers (members of Venom, Voivod, Celtic Frost, etc.) bellow into the microphone. Hard and heavy, ''Probot'' is a first-rate re-creation of the soundtrack of Grohl's bong-inhaling youth in all its unrelenting, doomy, gloomy glory. And for a lark, it aims for (and hits) a few bull's-eyes, including the whiplashing ''The Emerald Law'' and the postapocalyptic death march ''Ice Cold Man.''
In the '80s, such severe indie metal had actual mystery and allure. These days, though, the thrill is largely gone. When Motorhead's iconic Lemmy croaks, ''Looking for some relief in your miserable life/You need some rock & roll and you'd better get it right'' on ''Shake Your Blood,'' the result is more amusing than menacing. Other songs, with their demonic-frog vocals and references to archangels and ''scenes of mass decay,'' are unintentionally funny too. Despite the singers' seriousness, ''Probot'' lies somewhere between homage and howler. It's easy to imagine Cobain, wherever he is, reveling in its ludicrousness. But is that a good thing?