Energy core
From Halopedia, the Halo wiki
Summary
Energy cores are devices consisting of four energy projectors in the shape of a three-sided pyramid that project streams of energy into it's hollow center. The three streams combine into a ball of energy that is kept 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 moved or touched violently. They are found in Forerunner stations, such as the Halos.
