Energy core

Energy Cores are Forerunner devices consisting of three oversized Power Cores in the shape of a three-sided pyramid that project streams of energy into its hollow center. The three streams combine to form a pink ball of energy that is maintained in stasis. The purpose of these devices is unknown, although they could be a battery-type energy source. They are highly explosive (four times the power of any other explosion alone) if damaged or rammed violently but can be pushed easily. If they are hit, they will become unstable and turn red, but will eventually stabilize and turn blue again.

They are found in Forerunner installations, such as the Halo Array.