"Underworld of the Soul
The Edfu Building Texts speak at length about the presence of this subterranean domain beneath the island of creation once located on the edge of the Giza plateau. Referred to as the Underworld of the Soul, this structure was used by the divine individuals known as the Shebtiu to conduct strange ceremonies, described as acts of creation, using hand-held power objects. They are said to have gained their radiance from another much greater object described variously as the embryo, the seed, the egg, the lotus or even the benben, or phallus stone. This was seen to be the creative source of the island, embodying both the male and female regenerative powers. It is not stated exactly what this object might have been, although the indications are that, similar to the hand-held power objects used by the Shebtiu, it could have been a conical-shaped stone resembling the so-called lingams placed in underground shrines inside some Hindu temples. These too are seen to embody the dualistic regenerative powers of first creation.
Could this be what awaits discovery in Giza's underworld domain - powerful lingam stones that were once used in bizarre rites by the precursors of dynastic Egypt? Is this what will be found inside the Chambers of Creation, the so-called Hall of Records, if it is indeed discovered over the coming year?
That the ancient Egyptians believed that a physical object of immense creative power lie beneath the sands of Giza does not seem in doubt. Among the body of magical literature known as the Coffin Texts it speaks of something described as "the sealed thing, which is in darkness, with fire about it." It is said to contain "the efflux of Osiris", the god of the underworld, and was "put in Rostau", the name given by the ancient Egyptians to the Giza pyramid field. The text in question goes on to state that this "sealed thing" has been "hidden since it fell from him (Osiris), and it is what came down from him onto the desert of sand".
( from here )
In connection with my previous comments, a pillar of metal (what came down to the sand) might be a little understated as being what was/is beneath the Great Pyramid and several other pyramids, and responsible for the harnessing and transmission of 'energy' that could be used by those who used it.
The staffs depicted in use by the Gods always show a forked prong at the base, and never touched the ground. Other personages who used staffs had them resting on the ground; and hand-held power objects are also one aspect of an 'energy' device.
I haven't had much luck in finding a translation of the Edfu temple's texts, so cannot really contribute much more than what Collins has written.