A viral post on Chinese social media of what the poster claimed to be a mysterious animal swimming in the crater lake of Baekdu Mountain on the China-North Korea border has reignited interest in a mythical creature in the lake, Chinese news outlets reported on Monday.

The video, captured from an observation deck situated 500 meters above the lake, shows a dark object traversing the water's surface. The still surface of the lake is perturbed by the object seen gliding beneath, which leaves a trail of waves and ripples along its path.

Staff at the national park responded to local news sources, saying that it was impossible to determine what the object was due to the video's poor quality. The staff suggested it might be a certain feline species living in the mountain ranges spotted swimming in the river.

The incident is not the first time a mysterious creature has been allegedly spotted in the lake. Since the first reported sighting in 1962, dozens of people so far have claimed to have witnessed the so-called Heavenly Lake monster, evoking comparisons to Scotland's infamous Loch Ness monster. Most recently, in 2020, a staff member at the lake reported seeing a 2-meter-long object swimming around, according to local news reports.

The Chinese local government, which holds jurisdiction over roughly half of the lake following the 1964 Sino-Korean Border Agreement, has actively promoted its reputation as a home to a mystery creature as a public relations strategy to boost tourism.

Unfortunately for mystery hunters and monster enthusiasts, the region’s geography makes it all but impossible for such a creature to inhabit the lake. The 68-meter tall Changbai waterfall, which pours down from the otherwise isolated crater lake to the nearby Songhua River, prevents any living species from climbing across and entering the lake on its own. This lends credence to earlier speculations that the observed creature could be a mountain-dwelling feline species that happened to be swimming in the lake, if anything.

Other factors also make the lake an unsuitable habitat for aquatic creatures. Mount Baekdu, an active volcano, erupts periodically, with the latest recorded eruption occurring in 1903. These volcanic eruptions make it extremely unlikely for aquatic species to thrive in the long term. Furthermore, the lake is largely frozen from October to June, which also suggests it cannot be home to the mythic creature.

Despite such an inhospitable environment, the lake does contain some fish, though they were artificially introduced by humans. Historical documents show that the North Korean government brought freshwater fish like salmon and carp into the lake on at least four distinct occasions -- in 1970, 1984, 1989 and 1991 -- for ornamental purposes. Descendants of these fish have managed to prosper in the lake ever since, forming a more or less self-sustaining population.