Confounding music critics is not the Legendary Pink Dots’ modus operandi, but it must amuse them to peruse the long lists of micro-genres that writers have come up with. For nearly three decades, the iconic experimental rock collective has distilled practically the whole of recorded music history — tape loops, synths, folk elements, drum machines, electric guitars, and whatever else the perpetually rotating roster has at its disposal — into a cohesive whole. Plutonium Blonde, the latest addition to the Dots’ enormous discography, is as bleak and gloomy as anything they’ve done before; rays of major-key sunshine and jazzy goofiness barely poke through the creeping, goth-pop atmosphere.