“SUPERNATURAL” — (9:00-10:00 p.m. ET) OCTOBER 28 “Slash Ficton” (TV-14, LV) (HDTV) DOUBLE THE WINCHESTERS, DOUBLE THE FUN — Sam (Jared Padalecki) and Dean (Jensen Ackles) are once again on the FBI’s “Most Wanted” list when two Leviathans clone the brothers and go on a killing spree. The subject of a nationwide manhunt, Sam and Dean need to drop off the grid so Bobby (Jim Beaver) sends them to F...