The Dark and Light Shields are both unused multiplayer upgrades in Metroid Prime 2: Echoes. The only evidence left of them in the game are four unused sentences. Presumably, both of the upgrades were to serve the same purpose, of blocking attacks from the Dark and Light Beams, respectively. Whether the Annihilator Beam would negatively affect the shields or not is unknown.
In the final game, the Ingsmasher holds a similar technology. Often, it will hold its fist in front of itself, and create an orb of purple or white energy, to block damage from the Dark and Light Beams, though the opposite beam will still damage the Ingsmasher.
"Dark/Light Shield lost!"
"Dark/Light Shield acquired!"
|Metroid Prime||Spazer Beam • Screw Attack • Speed Booster|
|Metroid Prime Hunters||Power Bomb|
|Metroid Prime 2: Echoes||Thermal Visor • X-Ray Visor • Wave Beam • Wavebuster • Ice Beam • Gravity Suit • Ice Spreader • Plasma Beam • Flamethrower • Absorb Attack • Dark and Light Shields|
|Metroid Prime 3: Corruption||Ship Grapple Expansion|
|Super Metroid||Long Beam|
|Metroid Fusion||Grappling Beam • Spazer Beam|