In the Dark Ages, Christian mystics expressed their faith by lashing themselves with nasty-looking whips and looking for excuses to get burned at the stake. Their modern counterparts aren't as hardcore. They start freaky-ass rock bands and wail about Christ's blood over fiendishly distorted guitar riffs. On its debut, In the Valley of Elah, Kansas City's Tarkus Attacks sets a fine, self-flagellating example for its brethren. The duo preaches the good news of lo-fi prog rock by spewing instrumental shrapnel jagged enough to rip a sanctuary curtain and by screaming proclamations of faith like someone being tortured by the devil. Consisting of Chris Bohatyritz on guitar, lead vocals and occasional keys and Nate Lewis on drums and backing vocals, Tarkus Attacks lurches between polyrhythmic cadences and stomping breakdowns, channeling the fury of Samson slaughtering the Philistines. The band isn't completely nonsecular, however. Both the band name and the song "Tarkus Story" pay tribute to the 1971 Emerson, Lake & Palmer album — or, more precisely, its famous armadillo-tank-monster cover art. Christian heavy-rock bands are nothing new, but Tarkus Attacks' ecstatic primitivism is more likely to win converts than, say, Stryper.