One of the most original bands ever to gain a bankable following is beginning to sound too comfortable in its self-invented genre. Not that any other band has duplicated the formula: metalcore mosh with auctioneer-gone-mad vocals, followed by incantational harmonies and exotic-stringed acoustic breaks. And few other bands with such Zappa-like contempt for pop culture have landed on MTV. But more than half the tracks on Hypnotize follow the tried-and-true with professional polish--not a good thing for the band whose punky spontaneity is its hidden ace. When a jabbering, balls-out obnoxious incitement to eat patriots sounds too familiar and downright casual, there's a problem. Unlike May's sister release, Mezmerize--which was both more fun and more clearly political--Hypnotize's best tracks are the less frenetic ones: the title song's meditative, mid-tempo heaviness, the unclassifiable textures of "She's Like Heroin" and the nearly Queen-ish "Kill Rock 'N' Roll." It's time for System of a Down to shock its own system.