The Mongolian Death Worm is a snakelike creature reported to exist in the Gobi Desert. It is generally considered a cryptozoological creature, one whose sightings and reports are disputed or unconfirmed.

It is described as a fat, bright red worm, two to four feet long. The local name is allghoi (or orghoi) khorkhoi (хорхой) which means "blood filled intestine worm," because it is reported to look like the intestine of a cow. There are a number of extraordinary claims by Mongolian locals (such as the ability of the worm to spew forth a yellow poison that is lethal on contact, and its purported ability to kill at a distance). However, there are no known scientifically reliable sightings. Some believe the worm is actually a reptile or legless lizard because of the dry climate in which it lives.

Chief investigator of this animal is Czech author Ivan Mackerle. Dr. Karl Shuker also describes it in his book The Beasts that Hide from Man (2003), where he says it reportedly kills its victims by electrocution.

A joint expedition in 2005 by the Centre for Fortean Zoology, Cryptoworld and E-Mongol investigated new reports and sighting of the creature. Although they found no scientific proof of its existence, they do believe that such a creature could exist in the deep Gobi Desert along the strictly prohibited areas of the Mongolian/Chinese border. Future expeditions are planned for 2006 and 2007, where they will also investigate the legend of the Mongolian Almas (Алмас).

The color yellow is said to attract the worm.