A central technology of the grey aliens is the light beam. It provides illumination, can lift objects and people, and it seems to teleport people from within the beam in some cases. Its capabilities are certainly extensive and it seems to be a universal tool for the aliens.
Beam as light source and scannerEdit
This light beam seems to be a scanning device and light source as seen when one of their ships was searching for a lost alien vessel in upstate New York after Flight 549 crashed. Mike Millar saw the ship scanning the area with the light beam and when he got closer it, the ship disappeared and then reappeared right above him with its beam. This suggests that while the light beam is used to scan for things, it is not the only sensor on the alien ships. ("Tempus Fugit")
The way the beam lifted up Max Fenig while little light was seen and the alien vessel was stealthed suggests that the beam can be used without acting as a bright light source. Allowing the beam to be used while ships are concealed. ("Fallen Angel")
Generally, it seems to be white light though Samantha Mulder's abduction had her pulled out a window into a dull red light.
Beam as device that can move matterEditObjects and people in the beam's light can be lifted by it up into the alien craft, though when abducting people they are seldom taken this way. Cassandra Spender was taken using this method on the bridge that was a mass alien abduction site. ("The Red and the Black") The way this beam lifted up Max Fenig shows that it can lift and immobilize a person while scanning them, teleporting them, or so forth. ("Fallen Angel")
Beam as immobilizerEdit
The beam is capable of immobizing a person. Many times in the series, abductees describe a beam or the intense light from a beam wide enough to encompass everything, paralyzing them. Either keeping them from moving at all or sapping their willingness to act.
For instance, Mulder recalls bright light during his sister's abduction and feeling unable to act when he had finally gotten his father's revolver out. ("Little Green Men")The light beam can penetrate through solid objects to immobilize people. Duane Barrybeing paralyzed so the grey aliens could experiment on him is shown here from both the interior view of his home and the exterior view of the craft hovering above his home projecting the light beam down upon him. Crippling people in this way must be to keep them from struggling against the aliens or fleeing from the experiments performed upon them.
Beam as weaponEditWhen the faceless alien rebels attacked adductees at the bridge, the alien vessel that arrived to battle the rebels used the light beam as a weapon that engulfed in flames and completely destroyed the rebels on the ground. The beams flashed on and off as it performed this function, obliterating the rebels in seconds.
Beam as teleporterEditFrequently, people disappear in a flash of light after an alien craft's beam appears around them. Often the flash of light is the only part of the beam that is seen. It is possible this is another device working in conjunction with the beam or the greatest function of the beam. Time loss is frequently experienced after one of these flashes as the beam bends time and space to take someone or something. An excellent example of its use would be the animals taken from the Fairfield Zoo. Each disappearing or becoming invisible (a side effect of the beam's use) in a flash of intense light.