John Whittlesey, leader of the New York Museum of Natural History's 1987 Amazon Basin Expedition, and his assistant Carlos, found an abandoned hut containing artifacts of the Kothoga tribe somewhere on the slopes of the tepui Cerro Gordo in the Upper Xingú Rainforest.
At the time of the hut's discovery, the expedition had recently split up over a disagreement about whether to ascend the tepui without permission from the government of Brazil. Whittlesey, Thomas Crocker, their aide-de-camp Carlos, and a few native porters continued up the mountain while the others turned back.
Crocker found the hut by accident when he veered off the path to study a plant. He discovered an overgrown trail leading deeper into the jungle, and Carlos and Whittlesey followed him to a clearing containing the crudely-built hut.
The hut appeared to be a center of worship of the Kothoga monster-demigod Mbwun. On either side of the doorway were stone tablets with carvings of Mbwun. Behind the hut was an overgrown garden containing brightly-colored plants, specimens of the Mbwun Lily.
An elderly Yanomamo woman was in the clearing when the party arrived. The old woman warned them not to enter the hut, telling the party that Mbwun would follow them and bring death to their people. She pointed at the crate and repeatedly yelled, "Devil! You're taking the devil!"
The floor of the hut was recessed several feet below ground level. In the middle of the hut was a tall mound of dirt, topped with a finely carved figurine of Mbwun. Around the edges of the hut were countless human skulls, all crushed at the base and bearing deep gouge marks.
Carlos was so disturbed by what he saw that his hair turned white. The native porters refused the enter the hut and fled while the scientists were inside. Even Crocker disappeared, telling Whittlesey he needed to take a walk.
Whittlesey removed several artifacts from the hut, including a wooden plant press, a shaman's rattle, and the Mbwun figurine. The figurine later became the centerpiece of the museum's Superstition Exhibition.
Whittlesey packed the artifacts in a specimen crate, using plant fibers he found in the vicinity as packing material. He sent Carlos back with the materials, a letter to his protégé Hugo Montague, and his personal journal. He continued up the mountain to find Crocker and disappeared.
The old Yanomamo woman's warning was prophetic, although not understood by Whittlesey or Crocker at the time. The devil she referred to was not the figurine, but the plant fibers, which were those of the Mbwun Lily. Both men did find the Kothoga. Crocker was killed by the tribe, and Whittlesey was forced to take an extract of the lily, which caused him to undergo a mutation and become Mbwun himself.