“The huge double pyramid is stuck between the cliff face and the ruined archway, piercing them like a bolt head. It's covered with strange symbols, many of which are not apparent immediately; as you inspect each part of this peculiar monolith closer you keep discovering more and more of them.
In most of these symbols there's some type of a cross taking the central position with other symbols being placed around them, such as filled and empty circles, brackets, and something that resembles the letter M (or maybe W).
It is emitting a noise in a strange way, as if the sound is played on a completely different channel and not at all affected by the acoustics of the cavern or interference from the sound of waves lapping against the rocks.
Its blue, green and purple gleam changes depending on the angle and distance from which you view it, which, combined with minute details of the symbols, makes the monolith always leave a slightly different impression whenever you glance at it.
”
- —In-game description