The Light Beam is a Luminoth Weapon created during the Luminoth-Ing War as a replacement for the failed Dark Beam. It fires beams of pure light powerful enough to phase through most creatures and set targets alight.
The Luminoth had soon found that their attempt to overload the Ing with their own power was ineffective, as the creatures were able to shrug off the Dark Beam easily, taking little to no harm from them. It was then that they had realized their mistake, and had started work on a new weapon, which would use Light to eradicate the Ing. The decommissioned Dark Beam was repurposed for opening portals to Dark Aether.
The new Light Beam had a much better impression than the Dark Beam. Being mostly composed of Darkness in corporeal form, the Ing were easily roasted by the deadly Light energies. What is more, the Light and Dark Beams were later developed to be used in mechanisms powered by their respective energies, such as the Light Crystal.
After the Luminoth's defeat, a Light Beam weapon module was later found by Bounty Hunter Samus Aran, who had used it liberally in her quest to restore Aether and defeat the evil Ing.
The Light Beam is very similar to the Plasma Beam, in the sense that both fire fast-moving coherent beams and set enemies on fire. Like the other two Luminoth beam weapons, it relies on an ammo supply to fire. When depleted, it can be charged up to fire a weak shot, which still deal damage (albeit at a lesser degree) and interact with Light Crystals and Light/Dark Mechanisms. The Light Beam deals heavy damage to Ing and Darklings and can open portals to Light Aether.
When used with the Charge Beam, it fires a scattershot burst that can deal heavy damage to one target or hit multiple targets. An add-on to the Light Beam, the Sunburst, fires a powerful blast of light that incinerates any enemy in the blast radius. It can be used on Light Crystals and Beacons to charge them with Light Energy. The Safe Zone a Charged Crystal or Beacon generates protects Samus from the caustic atmosphere of Dark Aether and deals damage to any Ing or Darkling that enters the field.
- Metroid Prime 2: Echoes (First appearance)