Mbwun was a humanoid creature created and controlled by the Kothoga Tribe. The Kothoga turned humans into Mbwun creatures using an extract of the Mbwun Lily. There was one Mbwun at a time; when a Mbwun died or was killed, the Kothoga created another one.
Anthropologist Julian Whittlesey discovered the Kothoga and their protector in Brazil in 1987. He is presumed to have killed the beast and was then forced to take the Mbwun Lily and become a Mbwun himself. He lived near the Kothoga until their tepui was razed for mining by the Brazilian government, and then, addicted to the now-extinct Mbwun Lily, followed the trail of his artifacts (which were packed in Mbwun Lily fibers) from the Amazon Basin, through Belém, back to the United States and eventually to the New York Museum of Natural History.
The Whittlesey/Mbwun lived undetected in the museum's sub-basement for years, killing small animals and drifters for food and rationing the limited supply of lily fibers, until the museum's directors moved the crates into a locked storage area in preparation for the upcoming Superstition Exhibition. At that point, unable to acquire the hormones from the Mbwun Lily to sustain his addiction, the Whittlesey/Mbwun began killing killing museum employees and visitors and eating the hypothalamus, which contained minute amounts of the same hormone. The resulting rampage became known as the Museum Beast Murders.
Mbwun 's presence is accompanied by a pungent odor often described as "goatish".