Tens of thousands of people watch a video from the national park where four upright creatures appear behind a group of bison.
Has bigfoot finally been spotted?
According to some Sasquatch enthusiasts, footage shot at Yellowstone National Park shows not one but four of the mythological creatures.
The footage shows bison roaming around in a snow-covered park - until four creatures walking upright appear in the background.
The footage posted by user Mary Greeley has been watched some 40,000 times since the end of December.
"News they don't want you to hear", says a caption as the clip starts.
The video, captured on camera near the tourist attraction's Old Faithful geyser, cuts away before the camera can take a closer look at the creatures.
Bigfoot is said to have flat feet - similar to a human's - and a footprint that spans over 40cm.
Enthusiasts have long hoped to find evidence proving the existence of a creature widely thought to be fictional.
Scientists believe that most supposed sightings are cases of misidentification of other animals or hoaxes.
Yellowstone National Park Spokesperson Al Nash told ABC: "Bigfoot sightings are not frequent, but it happens.
"People say a lot of crazy things about Yellowstone all the time and bigfoot is just one of them."
Despite its controversial status, the beast is a very popular cultural symbol in North America, and was used as one of the mascots for the 2010 Winter Olympics in Vancouver, Canada.
News Source & Video:: Has Bigfoot Been Spotted At Yellowstone?