It was the perfect setting for a metal showdown: a dilapidated Masonic temple in Brooklyn. Even better: this was the first area show in four years from Oakland experimental metal band Neurosis. The group — fronted by Steve Von Till, wearing what looked like red doctor's scrubs (or a mental patient's pajamas — your pick) — turned in a skull-fucking set that ranged from full-blown thrash to quieter, tuneful dirges ("Season in the Sky" was a highlight). Equally good were Atlanta dudes Mastodon, who opened for Neurosis with a satisfyingly long string of tunes from all their albums. While they didn't unleash any new songs, as fans were anticipating, it was one of the few times they'd performed "Hand of Stone" and "Trilobite" live. And despite the muddied sound (and two false starts at the beginning of "Aqua Dementia"), the four-piece still managed to sync up for some tricky lock-step grooves on jams like "Sleeping Giant."