Ascending a Mountain of Heavy Light is the second recorded collaboration between the Body and Full of Hell, two prolific American groups who consistently push the boundaries of heavy music. Their first teaming, 2016's One Day You Will Ache Like I Ache, was named after a Hole lyric, contained a Leonard Cohen cover, and was an extremely tense composite of the two acts' grind, noise, and sludge tendencies. As good as it was, Ascending immediately feels like a major step up from the two parties' initial effort. It's busier, better produced, and a whole lot weirder. In fact, it just might be the craziest thing either band has ever done. The album continues with the "gross pop" aesthetic of the Body's 2016 scorcher No One Deserves Happiness, adding a glossy sheen to a deconstructed amalgamation of several styles of metal (with elements of jazz, dance, and choral music). This is high-definition sonic wreckage, with a wide array of sounds processed and mutilated into an explosive yet tightly controlled maelstrom. A particularly notable emphasis is placed on the drums, which are a combination of live playing and programmed beats. Skittering trap hi-hats swerve off the rails on several tracks, adding a modern edge to brutally slow and heavy sludge drumming. There's also an enormous amount of glitch trickery involved, especially on opener "Light Penetrates" and brain-shredding centerpiece "Our Love Conducted with Shields Aloft," one of two tracks featuring legendary splatter-drummer Brian Chippendale of Lightning Bolt and Black Pus. The latter piece starts out like a massive storm, with swarms of drums and blaring saxophone along with Chip King's psychotic rooster crowing, and it just continually builds and breaks apart until everything is decimated. Full of Hell's Dave Bland provides the rhythm for "Master's Story," which starts out like a death disco anthem with a pounding 4/4 electronic beat and rhythmic growling, ending with a sheet of white noise and serrated guitar feedback. Utterly unpredictable and thoroughly devastating, this album slays from start to finish, and upholds both acts' reputations as groundbreaking artists.