Source: Bestiary 2, pg(s). 194
A mothman is a strange, lonesome creature somehow either entwined with or attracted to serious disasters. Almost unknown to scholars, their origins and details are merely guessed at. The mystery surrounding mothmen has led to their prominence in folklore which has made them known to most only by dark myths rather than solid facts.
Humanoid in shape but with hints of insectile heritage, a mothman stands nearly seven feet tall but weighs as little as 100 pounds. Their body looks reasonably human except for the dark gray color of their skin. From its shoulders emerge huge wings that shimmer in every possible color. Its insectile face resembles a grasshopper's, and is filled with two huge eyes that glow with hellish inner fire.
Habitat and ecology
A mothman can be found almost anywhere precluding disasters or miracles. They seem to prefer to appear in areas on the edge of civilization and have been seen in isolated places from Ustalav to Qadira. They seem to be supernaturally attracted to sites of disasters before they occur, and wherever they appear disaster follows shortly thereafter. Even more unusual is the fact that many of those who witness the mothman or live near where the mothman was seen report experiencing strange visions of these disasters before they occur. There have never been any reports of someone witnessing more than one mothman and it is unknown whether there are multiple mothmen or if it is a unique creature. Little is known of the ecology of these creatures as they are rarely seen and no mothman body has ever been discovered.
Their are many rumors surrounding Golarion's mothman. The first recorded sighting of the Mothman was in 4584 AR in the town of Bronze Bridge in Taldor. This sighting preceded the collapse of the town's bridge which caused the death of dozens of people. This was the first time the mothman's appearance heralded a disaster. Mothmen are surrounded by a host of other rumors. Supposedly the mothman chases those who witness it but rarely catches them. This seems strange as the mothman has been reported to fly at incredible speeds, faster than even the largest dragons without moving its wings. This supernatural speed makes the escape of those who witness it seem improbable, leading some to theorize that the mothman allows them to escape. Witnesses have reported coming across people staring into the hellish eyes of the mothman, yet those who were allegedly transfixed by the mothman's gaze later claim not to remember it. Rumor also claims that those who see the mothman are sometimes followed by it, with other people witnessing the mothman near the original witness's home. Finally some of those who have witnessed the mothman have reported later being effected by poltergeist-like phenomena of banging doors, breaking windows and moving furniture.