The creature is said to be hidden somewhere in the forest near North Yankton. It was discovered by a Modder who had traveled out of the map and found what was said to be a horrifying, skeletal humanoid sitting in the middle of the road. He got out of his vehicle to investigate, and the creature screamed violently. The player's character died of unexplained reasons.
When the Modder spoke about his encounter with the creature online, Rockstar immediately patched the area off. Since the area is no longer available to be explored, the creature can not be heavily disputed, thus making it somewhat unlikely.
Since Rockstar patched the area so quickly, it can be assumed that they were trying to cover up something. This may possibly be because of the creature, however what makes it more mysterious are the reasons why the area was sealed off. The sense of the myth becomes quite suspicious and unnerving.