The unknown Wraith beam has been seen in use once. Major John Sheppard observed it when the Wraith were culling Orin's planet. After a dart was seen using its culling beam, it flew over an area where a beam formed and went into the sky. The purpose of this beam is unknown. Perhaps it is a kind of collection beam that transports humans collected by darts to a hive-ship in orbit. Considering it was active during the rest of the culling and caused no apparent damage, the beam is most likely not a weapon. (SGA: "Letters from Pegasus")
beam fully formed