This cryptid is said to lurk in the volcanic crater lake on the China–North Korea border. Since the 1960s, witnesses have reported serpentine, seal-like creatures, sometimes in groups, rising from the lake’s surface. In 1985, a state-backed expedition recorded over 100 sightings in one summer, sparking national media attention. Even today, tourists occasionally film unexplained shapes and ripples in the clear mountain waters, keeping the mystery alive.