For all its good points, metal, as a genre, has never had much of a sense of humor. Individual metal-heads are often funny, charming people, but as a scene, it’s often on the defensive, forced to act like its conventions, all the make-up and over-the-top satanic imagery, is, like, totally bad ass and not at all ludicrous. Providing a rare release from all that seriousness is Gwar, whose musical persona (Spinal Tap meets KISS meets a particularly bad batch of LSD) pushes those trappings to a cartoonish extreme, employing elaborate stagecraft, impressive costuming and incredibly bad taste. Formed as a lark by a handful of Virginia musicians and art students in the mid-'80s, they’ve now spent almost 30 years as metal’s Merry Pranksters, transforming themselves into a band of grotesque intergalactic marauders straight out of the pages of Heavy Metal magazine to simultaneously satirize and revel in the genre’s most envelope pushing elements. Though they tour almost non-stop, you never quite know what to expect walking into one of their shows; except that there will be blood and lots of it.

There’s no denying that the musical end of Gwar’s shtick, all those albums of epic, head-banging thrash, is a bit perfunctory, but that being said, it’s not bad, just sort of standard. Here, the cover of Kansas’ “Carry on my Wayward Son” was something of a surprise, but beyond the expected crunchy riffs and obscene lyrics, there is little else to report. The real draw is the special effects spectacle of it all (maybe the Shepherd should have sent a theatre critic instead), which brings amazing production values to the most taboo-trampling black humor imaginable. The storyline for this tour begins with the booming voice of god, deciding to do something about that bothersome Gwar once and for all, after which the group does bloody battle with a number of his emissaries, including Romney, Obama, Hitler, a portly priest, and finally Christ, who, following a gruesomely perverted Passion Play, is resurrected as the hulking Super Cyborg Jesus, only to be savagely dispatched once more. The whole gory Grand Guignol would simply be pathetically, childishly anti-social if the comedy didn’t work as well as it does, like the paradoxical twist ending which finds god himself admitting that he doesn’t exist.

There’s definitely fat to be cut from the show, particularly a sagging middle section where nothing much really happens, but if it was 20 minutes too long, their rabid fans didn’t seem to notice. The band comes through town about once a year, and indeed it felt almost like a holiday, with its own traditions and customs, like fans wearing white t-shirts so they can proudly display how much fake blood they were splattered with (it’s like a Gallagher show, you might get wet). Watching a guy with a Gwar neck tattoo put on the new tour shirt before the show was even over made it easy to believe lead singer (and 43 billion year old Scumdogian barbarian) Oderus Urungus when he proclaimed Milwaukee the band’s favorite place to play. And in the end it’s easy to see why the metal crowd has continued to make Gwar, with all the expensive props and whatnot, a viable proposition. It’s a spot on parody of metal’s most deeply entrenched tropes, providing a dose of self-reflexive humor to a genre generally loathe to poke fun at itself, but you’ve also got to love something a lot to send it up so thoroughly. Plus it’s just plain fun. Everyone should see an alien warrior tear Hitler’s face off at least once in their life.