The Flatwoods monster is a humanoid creature of seemingly extraterrestrial origin. Its head is encased in a purple space helmet, which obscures its face save for its glowing white eyes. The rest of its body is sealed in a protective suit, with an armored breathing apparatus and a large spade-shaped frill on its back. The Flatwoods monster has no visible legs, its suit instead terminating to a bullet-shaped point at its bottom, with what appear to be small hover-jets around its waist, allowing it to float above the ground. Its long arms are tipped with large, three-fingered hands clad in large black gloves. It can be encountered in a random encounter in which, if approached or shot at, it will suddenly disappear along with a flash of light, or if it is a hostile variant, it will engage the party using teleportation to move around. It is possible for it to spawn alongside the mothman.
The Flatwoods monster purportedly took Colton Pickins onto its spaceship and performed experiments on him, however that account was disbelieved by the responding police force.
During combat, the Flatwoods monster may teleport around. It can regenerate lost health when near death multiple times. Killing it will count towards the "kill different kinds of human-like creatures" challenge.
The Flatwoods monster is based on West Virginia folklore. The Flatwoods monster was encountered by Fred and Edward May and their friend Tommy Hyer, who claimed to have encountered an alien creature after investigating a mysterious light that flew across the sky and appeared to have landed in the woods. The hovering monster was described as being ten feet tall with a green body and clawed hands, as well as a red face, glowing yellow eyes and a head shaped like an "ace of spades."