“Eclectic” is a redundant term when it comes to King Gizzard & The Lizard Wizard. Having released 14 studio albums in eight years—including five in 2017!—the Melbourne-based band has widely explored psychedelic rock, electric folk, jazz experimentation, and ’70s soundscapes. But on Infest the Rats’ Nest they pivot once more, returning to their heavy metal roots in a celebration of enduring adolescent influences. They pay heed to ’80s thrash metal like Slayer with the pummeling drums and clipped guitar riff of “Organ Farmer,” as well as ’70s-era Sabbath-influenced metal on tracks like “Mars for the Rich” and “Superbug.” The songs are tightly formed and often brief compared to the band’s back catalog, with the album driven by a core trio: vocalist and guitarist Stu Mackenzie, bassist Joey Walker, and drummer Michael Cavanagh. What hasn’t changed is the ecological concerns of Mackenzie’s lyrics, which embrace dystopian scenarios as the wealthy abscond to Mars and pandemics strike the Earth. If that suggests the end days, for King Gizzard it’s also a new direction.