The Mogollon Monster is reported to be a bipedal humanoid over 7 feet tall with inhuman strength and large eyes that some claim to be "wild and red". Its body is said to be covered with long black or reddish brown hair, with the exclusion of the chest, face, hands and feet. Reports claim it has a strong and pungent odor described as that of "dead fish, a skunk with bad body odor, decaying peat moss and the musk of a snapping turtle".
It said that the creature is omnivorous, nocturnal, and very violent. It is generally reported to walk with wide, inhuman strides; leave behind footprints measuring 22 inches in length. It was said to produce whistle sound or scream and explore campsites during night. It is also believed to consume deer and other wildlife by decapitating them.
Reported sightings range along the Mogollon Rim, from Prescott, Arizona north to Williams, Arizona, southeast to Alpine, Arizona, south to Clifton, Arizona, and northwest back to Prescott.
- The oldest known documented sighting of the Mogollon Monster was reported in a 1903 edition of The Arizona Republican, in which I.W. Stevens described a creature seen near the Grand Canyon as having "long white hair and matted beard that reached to his knees. It wore no clothing, and upon his talon-like fingers were claws at least two inches long." Upon further inspection he noted "a coat of gray hair nearly covered his body, with here and there a spot of dirty skin showing." He later stated that after he discovered the creature drinking the blood of two cougars, it threatened him with a club, and "screamed the wildest, most unearthly screech".
- Another early documented sighting was recounted by cryptozoologist Don Davis. During the mid-1940s he was on a boy scout trip near Payson, AZ, of which he gave the following account: "The creature was huge. Its eyes were deep set and hard to see, but they seemed expressionless. His face seemed pretty much devoid of hair, but there seemed to be hair along the sides of his face. His chest, shoulders, and arms were massive, especially the upper arms; easily upwards of 6 inches in diameter, perhaps much, much more. I could see he was pretty hairy, but didn't observe really how thick the body hair was. The face/head was very square; square sides and squared up chin, like a box".
- A member of the White Mountain Apache Nation in Arizona by the name of Collette Altaha stated in 2006, "We're not prone to easily talk to outsiders, but there have been more sightings than ever before. It cannot be ignored any longer." "No one's had a negative encounter with it," said Marjorie Grimes, who lives in Whiteriver, the primary town on the reservation. When asked about her encounter she reports that "It was all black and it was tall! The way it walked; it was taking big strides. I put on the brakes and raced back and looked between the two trees where it was, and it was gone!" Regarding local reports, Tribal police lieutenant Ray Burnette states that "A couple of times they've seen this creature looking through the windows. They're scared when they call." He stated "The calls we're getting from people — they weren't hallucinating, they weren't drunks, they weren't people that we know can make hoax calls. They're from real citizens of the Fort Apache Indian Reservation."
Generally the scientific community attributes creature sightings to either hoaxes or misidentification. As recently as the early 1930s, grizzly bears roamed the forests of Arizona. These may account for the early day sightings while other large mammals such as black bears, mountain lions and elk may account for the sightings of today.