The Flatwoods Monster is an alleged unidentified extraterrestrial or cryptid reported to have been sighted in the town of Flatwoods in Braxton County, West Virginia, United States on September 12, 1952. Various descriptions of the entity exist, but most agree that it was at least 7 feet (2.1 m) tall and that it had a black face which appeared to glow from within, and a black body. Witnesses described the creature's head as elongated, non-human eyes and as either being shaped like a sideways diamond, or as having a large circle shaped cowling behind it. The creature's body was described as being inhumanly-shaped and clad in a dark pleated exoskeleton.
After encountering the creature, several members of the September 12 group reported being overcome with similar symptoms which persisted for some time, which they attributed to having been exposed to the mist emitted by the creature. The symptoms included irritation of the nose and swelling of the throat. Lemon suffered from vomiting and convulsions throughout the night, and had difficulties with his throat for several weeks afterward.
A doctor who treated several of the witnesses is reported to have described their symptoms as being similar to victims of mustard gas.