In the vast expanses of the southern Gobi Desert, Mongolian nomads have for centuries spoken of the olgoi-khorkhoi — literally, the 'large intestine worm' — a bright red, sausage-shaped creature approximately two to five feet in length that reportedly lives buried beneath the sand. According to Mongolian folk tradition, the creature emerges from the dunes only during the hottest months of summer, particularly after rare desert rainstorms that briefly soften the sand. Its body resembles a thick segment of intestine or blood-colored animal entrails, and nomadic herders warn children never to approach such an object lying in the open.
The creature's legendary lethality takes two forms. Some accounts describe it as capable of spraying a highly corrosive venom — said to turn metal yellow and kill livestock on contact. Others attribute to it the power to discharge lethal electricity through the air, stopping the hearts of camels and humans at short range. The creature is said to move by inching forward along the sand or occasionally by leaping out of concealment.
Western awareness of the olgoi-khorkhoi was largely shaped by American palaeontologist Roy Chapman Andrews, whose 1926 book 'On the Trail of Ancient Man' described the Mongolian prime minister and other officials asking him to capture one of the creatures during his fossil expeditions in the Gobi. Andrews himself never saw one. In 1990 and 1992, Czech cryptozoologist Ivan Mackerle led expeditions specifically to search for the creature, collecting eyewitness testimony from herders across the southern desert, but never producing a specimen or photograph. Later expeditions by Richard Freeman of the Centre for Fortean Zoology and by British television crews have repeated this pattern.
Biologists consider the olgoi-khorkhoi most likely to be folkloric, possibly inspired by legless reptiles such as the sand boa or by a regional misinterpretation of the worm-lizard Tartar sand boa. Whether based in biology or not, it remains one of the most famous cryptids outside the Americas and Europe, and a symbol of the remote, still-incompletely-mapped Gobi.