The Brotherhood's most dangerous defensive weapon has come to the world of NWN. It uses the game's obelisk model (therefore SoU is required) and the standard invisible object model to emit a red beam (of negative energy) towards a target.
Basically, the obelisk can be named and tagged however you see fit. The only criteria for the whole thing to work is that the script that comes with the erf-file is placed inside the obelisk's OnHeartBeat event (which is already the case by default). The script causes the obelisk to search for a target within a given radius every six seconds. If one is found, an invisible object is placed ontop of the obelisk which fires the "laser". You can rename the cript too if you like, it won't mess up anything.