Unidentified Forerunner weapon

This Unidentified Weapon was an energy weapon used by the Forerunners during the Forerunner-Flood War.

Description
It was a white, claw shaped device that fired a bright blue bolt of energy. While it was activated it had a energy "base" that bolts were fired out of.

Trivia

 * The hilt for the weapon looks almost like a Constructor.
 * Along with it looking like a Constructor, the look of the weapon might be where the Covenant got the idea for the Energy Sword.