You know those scenes in horror movies when some creep (who, of course, turns out to be a skull-sucking monster from hell) opens its mouth wider than it should? With jaw unhinged, Code Orange's Underneath, out Friday, devours a body of extreme sounds — sludge, noise, metallic hardcore, doom, grunge, industrial and whatever else it takes to make the mosh pit swarm — to make uncompromisingly chaotic metal.