The Shining Trapezohedron is a fictional artifact appearing in H.P. Lovecraft's short story "The Haunter of the Dark" and Robert Bloch's sequel "The Shadow from the Steeple". The Trapezohedron serves as a window on all of space and time. By gazing into it, its wielder would summon one of the Outer Gods known as Nyarlathotep in his avatar as the eponymous Haunter of the Dark. In exchange for horrible sacrifices, the Haunter of the Dark would reveal other worlds and arcane knowledge.
The Shining Trapezohedron was a "crazy angled stone" created on the planet called Yuggoth and brought to Earth by the Great Old Ones before the emergence of the human race. Throughout its history it was associated with the legendary continent of Atlantis and the Pharoahs of ancient Egypt. Occultist and archaeologist Professor Enoch Bowen discovered it within a box of alien construction while exploring the ruins of the tomb of Nephren-Ka in 1843. Bowen returned to his home in Providence, Rhode Island with the Trapezohedron and its box the next following year, where he founded the Church of Starry Wisdom.
The Shining Trapezohedron was researched by Robert Blake, who deciphered a number of ancient texts concerning the stone. Following Blake's death, the stone was removed from the Starry Wisdom cult's sanctuary and thrown into Narragansett Bay by Dr. Ambrose Dexter. Unknown to Doctor Dexter, however, the constant darkness at the bottom of the bay ensured the Haunter of the Dark's perpetual freedom. For his trouble, Dexter was possessed by the Haunter, and eventually became one of the foremost nuclear scientists in the world, in charge of investigation of atomic energy for wartime purposes.