The Light Beam.
The Light Beam is a Luminoth weapon created for energizing Light Crystals & Light Beacons and killing creatures of Dark Aether by burning them with light. Samus Aran recovered it from Dark Agon in the game Metroid Prime 2: Echoes. The Light Beam can activate inactive Light Portals and greatly damages Dark enemies, such as Ing. The Light Beam can also open Light Doors. Its Charge Beam technique is called the Lightblast, which puts enemies on fire. If out of ammo, Samus can charge this beam to create a normal shot.
Samus hits a Warrior Ing with a Lightblast. Note how the blast covers a large area.
Once acquired from the Grand Windchamber, Samus could use the Sunburst, the Charge Combo for the Light Beam. It created a slow moving sphere of light that would be good for destroying slow-moving Dark enemies.
The Light Beam is similar to the Plasma Beam of Metroid Prime.