The Guai Wu is the name given to what is said to be a lake monster that lives in Heaven Lake (known as Cheonji in Korean) located in the peak of Baekdu Mountain within the Baekdudaegan and Changbai mountain ranges encompassing Jilin Province of China and the Ryanggang Province of North Korea. Some reports argue that there are an estimated 20 monsters.
The Guai Wu, meaning "strange beast" is a lake monster from Tianchi Lake, described as bigger than an ox, with a head like a seal, and a long swan-like neck. Skeptics point out that a nearby volcano erupted in 1702, probably destroying any life in the lake. However, others think that it could have somehow survived the volcano. It frequently appears to groups of witnesses. There have been over 400 individual witnesses.
The first reported sighting was in 1903. It was claimed that a large buffalo-like creature attacked three people, but was shot six times. The monster then retreated under the water.
In 21 to 23 August 1962, a person using a telescope reportedly saw two of the monsters chasing each other in water. More than a hundred people reported the sightings.
More recent reports describe the monster as having a human-like head attached to a 1.5 m neck. It is said to have a white ring around the bottom of its neck, and the rest of its skin is grey and smooth.
In 2007, Zhuo Yongsheng, a Chinese TV reporter said he had shot a 20-minute video of six unidentified creatures in the volcanic lake on 6 September. He later sent still photos to Xinhua's Jilin provincial bureau. According to a news report one of these showed the six "Nessies" swimming in parallel in three pairs. Another one of them featured the animals closer together, leaving circular ripples on the lake surface.
Zhuo said he had seen the six seal-like, finned creatures swimming and frolicking in the lake for an hour and a half, before they disappeared around 7:00 a.m. "They could swim as fast as yachts and at times they would all disappear in the water. It was impressive to see them all acting at exactly the same pace, as if someone was giving orders," he said. "Their fins—or maybe wings—were longer than their bodies."
In popular culture The Mountain Goats' 2008 album, Heretic Pride features the song, "Tianchi Lake" about the monster: "Backstroking on the surface, moonlight on its face / Floats the Tianchi monster, staring into space."