Back in the dinosaur days of the 1980s, punks and longhairs swore eternal enmity to each other. It took intrepid acts with roots in both worlds and three-letter acronyms — S.O.D., C.O.C., D.R.I. – to bridge the gap. Dirty Rotten Imbeciles’ third long-player not only cemented the hybrid between thrash metal and hardcore punk but also gave it its name. Crossover proved a few things: first, that hardcore could survive a brush with actual production quality; second, that the two genres weren’t that far apart; and third, that nothing got a pit going quite like gnarly thrash riffs sped up to punk speed. The songs are mostly distinguishable by their shouted choruses like “Tear It Down” and “Go Die!,” which is what makes them great. It kicks so much ass that it healed the schism between the two styles and taught future pizza thrashers like Municipal Waste and Toxic Holocaust how to make the dough.