DJs are a lot like horror-movie villains. Fist, DJs like Freddie or Jason or Martha Stewart are the agents of forward momentum in the plot, propelling lesser beings (club kids, campers, housewives) toward some kind of cathartic climax. Some spinners are Dr. Frankensteins, pulling switches to make their charges dance though ideally not like Peter Boyle in Young Frankenstein. Others lurk behind the decks like Nosferatu, waiting to strike when the moment is right. We could go on, but our advice is to draw the parallels yourself while throwing it down at Nightmare on Mass Street, Saturday's huge Halloween bash engineered by diabolical breakbeat pro DJ C-Vaughn (pictured), who spins the Friday-night dance-music program Liquid Buzz on KRBZ 96.5. Not wanting to face the crowds of willing flesh on his own, C has booked some major slashers, including Factor E (who could well be the Michael Myers of breakbeat) and DJ Fixx (um ... Pinhead?). Anyway, they're all good, and we'll get to see some scrappy newcomers battle it out when Kid Domino faces Ryan Espey and Bucho takes on Clockwerk. Death to all who fear the beat.