Even amid peak-grunge moodiness, few Nineties breakthroughs were as bizarre and bleak as TOOL’s full-length debut. Structurally, Undertow presents a primordial kind of TOOL-ing, hinting at the heady prog complexity to come while chewing through moments of mega-detuned, Southern-styled sludge (“Prison Sex”); its most enduring hit, the ink-black “Sober,” is marinating in a woozy, two-note slow-drip. A must-have record, we got pulled into TOOL’s Undertow for life.