Slipknot thrashes, takes five, thrashes, takes five and so on

“They said we were an abomination.... Then they said we were done,” Slipknot’s ghoulish frontman, Corey Taylor, noted midway through his group’s clamorous concert Saturday at the Forum. Then the masked metal band plowed into the Grammy-nominated single “Duality” from its latest album, “Vol. 3 (The Subliminal Verses).”

The nine-piece band from Des Moines has obviously disproved the doubters of its gimmicky thrash. It’s sold plenty of albums, been the highlight of two Ozzfest tours and garnered two Grammy nominations.

But beguiling nondisciples is another story. Not that Slipknot’s show isn’t arresting. With two crazed percussionists bookending the core band on hydraulic platforms with pummeling snares, plus a DJ done up like a skeleton and Pinhead keyboardist, the show suggested “Hellraiser, the Musical.” Take away the hype and what’s left is a fairly solid meld of scream-core and melodic dark metal.

But excessive intermissions proved to be Slipknot’s downfall. Just when the momentum reached fever pitch, the stage would black out. They may have needed breathers from the masks, but for a band that seems to go all the way lyrically and rhythmically, you’d think they would have sweated it out.