At the Orpheum on Sunday, October 4

Mastodon has got to be one of the most humble metal acts around these days. While the Atlanta outfit has been having a banner year, packing metalheads into venues around the globe in support of its mind-melting prog epic, Crack the Skye, the foursome respectfully bowed out of a headlining spot on its current trek to salute the sheer brutality of its tourmates, cartoon supergroup Dethklok. Judging by the frenzied roar that filled the Orpheum on Sunday night for the, um, animated act—which is usually seen in cartoon form on the Adult Swim show Metalocalypse—it was the right decision.

Best described as extreme metal’s answer to Spinal Tap, Dethklok gave a performance that was just as much about roasting the heavy-music community as it was about getting a crowd of heshers to bang their heads. The ensemble succeeded on both fronts.

Though the concert kicked off with a video intro that set up the premise of Metalocalypse—in which the globe’s superpowers conspire to prevent the insanely popular Dethklok from taking over the world—it was hard not to notice that the band that hit the stage, led by show creator Brendon Small, looked nothing like its small-screen counterparts.

While fictional singer Nathan Explosion is a barrel-chested, raven-haired metal god, Small is a fairly trim dude with a cropped haircut. Furthermore, grey-haired session guitarist Mike Keneally isn’t exactly the spitting image of either of the cartoon’s Scandinavian six-stringers, Toki Wartooth and Skwisgaar Skwigelf. Regardless how it looked, though, the flesh-and-blood version of Dethklok expertly ripped through its catalogue.

“Hatredcopter” assaulted the audience with a barrage of burly metal licks and drummer Gene Hoglan’s precise blast beats. The fist-pumping anthem also had Small performing double duty at the mike, screeching out the snotty vocal parts of imaginary skin-pounder Pickles as well as the guttural grunts of Explosion. Fan favourite “Murmaider”, a song about, well, mermaid murder, had the crowd chanting along with Small’s checklist of shivs, ropes, and laser beams before the outfit plunged into a squealing thrash section.

Dethklok finished the night with “Fansong,” a tune that both berates and praises its followers. Oddly, the closing number played without any visual accompaniment. Even without the smoke and mirrors, the live band killed it with its brain-bashing riffery.

Mastodon’s was, surprisingly, just as visceral as Dethklok. Throughout the set—a full performance of Crack the Skye with a couple of older songs tacked onto the end—footage of astral planes, swirling Spirographs, and even a sword fight in hell between Rasputin and Satan flooded the screen. As impressive as the visual aspect of Mastodon’s show was, the group’s performance was riddled with sound problems. Opener “Oblivion” should have been thunderous with its pounding drum work and chugging guitars, but the vocal mix was absolutely awful. Bizarrely, only drummer Brann Dailor’s backup vocals were audible. Thankfully things got better as the night went along.

With his gruff growl, bassist Troy Sanders took charge on “Crack the Skye”, a doomy march punched up by Brent Hinds’s fret-burning guitar solos. Though the band brought its A game on heavy space jams like “The Last Baron”, Mastodon’s encore of “Circle of Cysquatch” found Sanders once again screaming into a broken mike.

Opening act Converge faced some difficulties of its own. While the long-running combo put on the most energetic performance of the night, there was just one problem: you couldn’t see any of its members. While the group fully freaked out on metal-hardcore hybrids like “No Heroes” and “Concubine”, it was obscured by darkness on the ill-lit stage. But even though singer Jacob Bannon appeared as nothing more than a silhouette, between sprinting across the stage, beating the mike violently against his chest, and leading the fans up front through a host of gang chants, he and his Boston band were truly something to see.