Courtesy of The British Museum

Neighbors were appalled when Signora Reffoli gave birth to quadruplets in 1902—not only because the woman was rumored to be a witch, but because her children had skeletal faces and bodies.

The remote Italian village of Túfaschiagna had a long history of strange happenings, including mass hallucinations, well water turning strange colors, and at least two olive trees bursting into flames.

While no one could explain how Signora Reffoli conceived, she raised the children in her stone hovel at the edge of the village. Several noted biologists arrived from the University of Milan to study the children. They discovered that the siblings “communicated through a complex system of deep-throated sounds, like the ribbit of large frogs.” None of the children had eyes, but they would play a game by stuffing their sockets with soil, stones, and grass.

The researchers returned two months later to find that Signora Reffoli and the children were gone, and their house had been torn down. “None spoke of their disappearance, or they claimed to know nothing, yet all the while exchanged anxious glances with each other, as if guarding a terrible secret,” wrote one Dr. Bernardino in his notebook.

To this day, visitors claim to hear a chorus of frogs at night, even in the dead of winter.