With strong nods to Judas Priest, U.D.O. make heavy metal in its purest form. Forged around frontman Udo Dirkschneider, the German outfit craft hook-laden heavy-hitters with chugging power chords, perfect for headbanging. Their debut album, Animal House, created the template for everything that would follow. U.D.O.'s 16th record, Decadent, is a metal tour de force and testament to their longevity.