Helicoprion were a long-lived genus of shark-like fish that prowled the oceans 290-250 million years ago before vanishing in the Early Triassic period. Almost all existing fossil specimens consist of impressions of the unique circular patterns of helicoprion teeth known as "tooth whorls," similar in pattern to a circular saw.
Ghost helicoprion are the spectral remains of these prehistoric fish. They swim through the air as if underwater. Given where the spirits are found, it is suspected that the various species of helicoprion lived off the southwestern coast of Gondwana, and later, Pangea.
Ghost helicoprion (gōst/HE-lē-KOP-rē-on) do not mate or produce offspring and, like most spirits, they are presumed to be immortal until banished. The collective noun for a group of ghost helicoprion is a shoal. Ghost helicoprion tend to be solitary creatures, though.
Ghost helicoprion are highly dangerous and are not to be approached. Although they are largely non-corporeal, their whorling circular teeth can do a great deal of damage, easily taking off limbs which they are unable to swallow or digest.
The ghost helicoprion have been found in Western North America, as far north as the Canadian Arctic, as far south as Mexico, and as far east as the Mississippi River. This means that the ghost helicoprion is rather prolific, appearing in Thunderbird, Mishipeshu, Baja, and some parts of western Solaris Province. There have been unconfirmed sightings of the ghost helicoprion east of the Mississippi, but those have never been reliably substantiated.
Like a typical ghost, helicoprion are entirely spectral. They do not eat, breathe, eliminate, or mate.
There are not magical uses for the ghost helicoprion. They cannot be trained and, being spectral, have no parts which can be harvested for magical uses. A genuine ghost helicoprion tooth would fetch a tidy sum from collectors, but so far only fakes have surfaced.
Like most ghosts, they can be banished or warded against, but it's quite important to note that the physical properties of their bite can be quite effective in ways that standard ghostly attacks are not. Likewise, they are exceptionally fast and persistent once they have taken notice of potential prey. Spells that cause a blinding flash are particularly effective at disorienting them. They have shown no signs of gaining sentience in their spectral state, so attempts at communication or reason have proven entirely ineffective.