In 1992, an anthropologist named Neil Whitehead arrived in the capital of Guyana, a small, heavily-forested country on the northern edge of South America. From there, he took another small plane from Georgetown to a village in the forest-covered Pakaraima mountains.

At the time, Whitehead was researching the archeology of a remote part of the country, near the borders of Venezuela and Brazil.  He was working with the Walter Roth Museum of Anthropology to document the presence of urn burial sites.

The British academic had studied at the University of Oxford, and colleagues say he was a brilliant historical researcher. Decades of work convinced Whitehead that there were dense, wealthy societies in the region, as in the myth of the city of gold known as El Dorado. This vision challenged 1980s anthropological beliefs, but in 1990, freelance gold miners brought a gold chest pendant called the “Mazaruni pectoral” into the Walter Roth Museum. It had been dredged from the bottom of a river, and the design didn’t belong to any known metalworking tradition.

Whitehead suspected the pectoral had been produced by a large civilization, on the so-called Guiana Shield, a geological region in South America that spans Guyana and the surrounding countries. He believed that urn burial sites indicated signs of a more complex, settled civilization. So he set out to search the area where the lost city might have been. But soon after he arrived in the village of Paramakatoi, he was interviewing a nurse, who told him what he should really be investigating: kanaima.

Kanaima was the name given to people with strange powers and stranger rituals in northwestern Guyana, eastern Venezuela, and south into Brazil. They were said to transform into jaguars or anteaters. They could travel instantly over vast distances. And they were much-feared because they were known to attack lone victims as they walked through the forest. Considered by some to be “dark shamans,” kanaima emerged from a wider landscape of “assault sorcery” that stretches across Amazonia. But there were also aspects of kanaima–such as the role certain plants play–unique to the region.