When producer Prince Paul had a disillusioned phase in the early ’90s, he put together a series of demo beats that he’d later pinpoint as some of his must frustrated and darkest work. And when he gathered a few rapper friends who had a similar disillusionment (and some bad experiences with the Tommy Boy label) in common, they all struck on a concept so singularly weird and morbid for rap that it might’ve been universally rejected by the industry if one of those rappers hadn’t also kicked off one of hip-hop’s greatest institutions shortly after the initial demo recordings were cut. The presence of RZA, billed here as The RZArector, might’ve made the ’92-originated/’94-released 6 Feet Deep an easier sell once Wu-Tang started conquering rap at the end of ’93. But even if RZA sounds every bit as diabolical mixing gruesome imagery and deep philosophy here as he did on 36 Chambers, the dark appeal of Gravediggaz’ sound hinged on a collective effort, one that fellow members Too Poetic (a/k/a Grym Reaper) and Stetsasonic alumni Frukwan (a/k/a the Gatekeeper) rounded out with the kind of zero-fucks mania that only comes from being spurned by the mainstream. Their lyrical hyperbole pushes hardcore street rap into territory far beyond gangsta turf into a grimness that earned the infamous subgenre sobriquet “horrorcore.” But as gimmicky as that might seem — “1-800 Suicide” plays out like a self-harm instruction manual, the maniac-on-trial concept “Diary of a Madman” pushes courtroom crime drama into Wes Craven turf, and “Bang Your Head” is doom metal for heshers who prefer analog-synth basslines to drop-tuned guitars — it works because these dudes commit, weaving some of their most incisively deep lyrics in with the blood-and-guts shock value and delivering it like the furious verge-of-oblivion rejects they felt like in ’92.