Mukumuku

The Mukumuku are a race of large, yeti-like creatures. They are called "mukumuku" for the sound that they make. They are native to the Highlands and occasionally wander into Mineral Town or the Wood. While friendly and normally docile, they do become defensive when harmed. Since the pandemic known as the Sickness, they have become fearful of humans and will kill humans if they see them, fearful of catching the Sickness once again.

In the Winter War, the Mukumukus respond to the killing of a certain member of their species with open hostility towards humans, actively seeking out and killing humans. While the killing of the certain Mukumuku began the general hostility from the race, the killing of Lumina Hawthorne and Rock Ricardo began the outright war between humans and Mukumuku.

Despite human access to weapons, the Mukumuku were too powerful for them, forcing humans to hide in their homes. It was not until Marlin Stanton descended the Highlands to explain to Harris Moore how to defeat the Mukumukus that the war came to an end. Eventually, Harris was able to ensure the destruction of the Mukumuku by finding fleas with the Sickness, infecting himself, and transmitting the disease to the creatures, leading to their near annihilation.