Gene Roddenberry created “Spectre” in 1977, a pilot for an occult-themed horror show that never went to series. It’s as far as you can get from the rationalism of Star Trek, about an occult detective fascinated by evil who investigates Satanic cults, possessions, trances, mediums, succubuses, and family curses. The creature on top is the demon Asmodeus, not a Gorn, incidentally. Majel Barrett Roddenberry played the witch, Lillith.
Gene always seemed to believe that the best way to keep audience attention was through a recurring cast, which is why he created a show like Star Trek instead of an anthology series like the Twilight Zone. I suppose he figured a recurring occult detective (with a Dr. Watson and a witch housekeeper) was the best way to take on the horror genre.
It’s one of many pilots Gene made during the 1970s but failed to get to series, like Genesis II, Planet Earth, and the Questor Tapes, all of which contributed to the sense that Gene was a one-hit wonder or has-been, a sentiment that explains why Gene was so ferociously controlling on Next Generation: he didn’t want Trek taken away from him.