If you listened to High On Fire's excellent album from earlier this year, or perhaps to Mastodon's debut, and thought “this is great, but I wish everyone in the band was drunk and really mad at me,” then Canadian stoner/sludgers Bison B.C. have an album you might be interested in.

In fact, it's hard to think of a metal fan who wouldn't be interested in Bison B.C.'s second full-length, Dark Ages. You like thrash metal? BBC can thrash with the best of them. Death metal? James Farwell and Dan And sound like they're tearing their guts apart with every gravelly scream. Classic metal? Guitar harmonies galore. Black metal? Dig the atmospheric interludes, sometimes accented with barely-audible keyboards. Prog metal? These winding epic tunes jump from full-tempo highs to dynamic, ringing lows across runtimes that range from five minutes to nearly nine. Stoner metal? Like High On Fire, BBC have mastered that crunchy, fuzzy, somehow crystal clear guitar tone, pulling it through dragging sludgy bends and bringing it down on hammering power chords—it's stony, angry, and incredibly heavy, as if Farwell and And were shouting their spaced-out lyrics against the sounds of the Earth being created. None of this is new for the band, but more so than ever before, all of these elements are brought together into songwriting so tight that every moment fast or slow, even in the eight-minute tunes, is packed with heaviness, intensity and momentum in levels that more extreme bands have to condense their compositions into two-minute technical bursts to achieve.

Opener Stressed Elephant is a tour de force, spending eight minutes exemplifying pretty much every element I've just described before dropping off into a clean-guitar outro reminiscent of blues or folk music. These clean interludes will appear again on the album; they're one element that is new, and will remind Opeth fans of Watershed. They punctuate the songs with a bit of dynamic variation that does nothing to hinder the album's all-important momentum; in fact, listeners are not likely to find anything that does. By the time the album closes out with Wendigo pt. 3 (Let Him Burn) (the third part of a series whose first two installments were highlights of the band's last album, Quiet Earth) you may suddenly realize that you're exhausted, having been arrested by the album's breathless pace for 47 minutes without realizing that much time was passing. That speaks to what's most remarkable about Bison B.C.: the ability to craft massive prog tunes that never drag. The most die-hard prog metal fan will tell you that even masterpiece albums like Holy Land or Paradise Lost can be tough to get through without a breather; BBC integrate prog elements like rhythm changes and dynamic shifts into their sound so seamlessly that you hardly even notice they're there, giving Dark Ages a listenability that belies how challenging and intricate it really is.

Here's what you need to know about this album: it's heavier than you'd think possible. It takes the High On Fire/Mastodon school of thrashy stoner/sludge to new heights of ferocity while also bringing it subtly in touch with metal's old school. It is, essentially, badass. Those who'd like to get their music in the form of adrenaline shots should consider this a must-buy.