Over the years, we’ve heard about some of the encounters people have had in Colorado with what they say is Bigfoot, but back in the 1800s, legend has it that there was another monster living deep in the Rocky Mountains.

Known as the Slide Rock Bolter, this Colorado cryptid resembles a large, whale-like creature with a huge head, small eyes, hooked tail, and very large mouth. The mountain monster was first talked about by miners and lumberjacks that were working near the slopes back in the day. Stories say that the Slide Rock Bolter would sit at a 45 degree angle, latched onto the rocks, until it spotted tourists. Then, it would then use its powerful body to slide down and swallow them up, and after, with the help of its hooked tail, would climb its way back into the mountains. It was apparently responsible for at least 10 missing tourists a year, and some even say that the monster completely destroyed the mining town of Rico during one of its feasts. When tourists weren’t around, the Slide Rock Bolter would eat anything else in its path, like bear, deer and elk.

There haven’t been any recent sightings of the Slide Rock Bolter, but many believe that evidence shows it could still very well be alive, but dormant. Other theories say that maybe it was only ever a group of lumberjacks just trying to explain a rock slide.