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 if moved or touched violently. They are found in Forerunner stations, such as the Halos.
