The new trailer for The Mummy introduces us to Ahmanet, an ancient Egyptian princess who does not fuck around. In the trailer, Ahmanet reacts like most of us would when rudely awoken from a millennia-long slumber: By crashing birds into planes and destroying London with supernatural mind powers. With her morphing double pupils, Ahmanet both embodies this “new world of gods and monsters” and represents one of humankind’s oldest horror stories.

The curious nature of Ahmanet’s eyes isn’t a random scare tactic; it’s a callback to the concept of the pupula duplex, long perpetuated by folklore. For centuries and across cultures, it has been believed that a person with two pupils in each eye is someone who possesses an “evil eye” — and the power to bring illness and pain to those they envy. The earliest reference to a pupula duplex is in Pliny the Elder’s 77 C.E. tome, Natural History:

There are people of the same kind among the Triballi and the Illyrians, who also bewitch with a glance and who kill those they stare at for a longer time, especially with a look of anger, and that their evil eye is most felt by adults; and what is more remarkable is that they have two pupils in each eye.

Typically, pupula duplex is considered a sign of witchcraft but there are the rare exceptions in which it’s more benign, such as the legend of the double-irised Chinese Minister of State, Liu Ch’ung. Regardless, just like the waxed figure of a double-pupiled man at Ripley’s Believe It Or Not, pupula duplex isn’t real. There is no evidence that the condition is an actual medical condition, despite what people with Photoshop skills may want you to believe.

A similar — and very real — actual eye phenomenon, however, is known as polycoria. This is a condition in which there is more than one pupillary opening within an iris. While the medical literature indicates that three cases of true polycoria happened between 1899 and 1920, only one case has actually been photographed and studied. In a 2007 paper published in Acta Ophthalmologica, a team of scientists discuss a 55-year-old man with polycoria, whose multiple pupils were elliptical rather than circular. While they determined that the muscles that encircled each of his four pupils developed independently from each other, they weren’t able to figure out why the phenomenon occurred in the first place.

A case of polycoria.
A case of polycoria.

But polycoria, though real, is admittedly less cool-looking than Ahmanet’s pupula duplex. If a vengeful princess with crazy eyes, along with an eternally youthful looking Tom Cruise, is your thing, you can check out The Mummy on June 7, 2017.

Photos via Wiley Online Library, YouTube/Giphy