Caterpillar fungus, the world's most valuable parasite, can cost up to $63,000 per pound

Caterpillar fungus has been used in traditional herbal medicine for many centuries and can cost as much as about $63,000 per pound.

• Caterpillar fungus is a hybrid of a fungus that kills and lives in caterpillars.
• It can sell for up to three times its weight in gold and can cost as much as about $63,000 per pound.
• Some towns in the Himalayas rely on collecting and selling this fungus for a living.
• Visit Business Insider's homepage for more stories.

Following is a transcript of the video.

Narrator: What would you do if a fungus invaded your body, and started consuming you from the inside? It sounds like something out of a horror film, but that's actually what happens to a certain type of baby moth.

The fungus eats its way through the helpless moth larvae and then sprouts out of their heads like a spring daisy. But this rare hybrid, the caterpillar fungus, isn't just totally fascinating, it's also expensive. Sometimes selling for more than 3 times its weight in gold!

Caterpillar fungus grows in the remote Tibetan Plateau and Himalayan Mountains but that's not the only place you can find it. Here we are in New York City's Chinatown. And nestled among countless drawers of dried mugwort leaves and hibiscus flowers,

There it is a small pile of 50 or so pieces of dried caterpillar fungus. Here, 1 gram of it costs about $30. But even that might be considered a good deal. Vendors on eBay, for example, list a gram for up to $125. The price is so high because this hybrid creature is incredibly rare.

It shows up for only a few weeks each year in remote regions of Nepal, Tibet, India and Bhutan. And even then, the fungus can be tricky for collectors to find, hidden amidst a sea of grass. For centuries, it's been a staple of traditional Tibetan and Chinese medicine.

Kelly Hopping: "Traditionally, it was used as a general tonic, for immune support."

For instance, a family might add half of this to a chicken soup. And it's even rumored that it can be used as a sort of Himalayan viagra though there's little evidence to back it up. People also buy the fungus as a gift or use it for bribes or as a status symbol. As a result, better looking pieces fetch a higher price.

Kelly Hopping: "It's all dependent on exactly the color of the caterpillar fungus, even the shape of its body when it died, all of these things that don't necessarily have anything to do with medicinal value make all the difference for the economic value."

In 2017, for example, high quality pieces sold for as much as $140,000 per kg, or about $63,000 per pound. Now, caterpillar fungus has always been pricey. But experts say its value really skyrocketed in the 1990s and 2000s because of a growing Chinese economy, and the resulting increase in disposable income. Which ultimately, helped drive a massive boom in harvest.

In the Tibet Autonomous Region, for example, collectors reportedly hauled out more than three times as much caterpillar fungus in the early 2000s, than they did in the 1980s. And now, many families depend on the cash it brings in.

In fact, experts say that up to 80% of household income in the Tibetan Plateau and Himalayas can come from selling caterpillar fungus. One district in Nepal reported collecting $4.7 million worth of caterpillar fungus in 2016. That's 12% more than the district's annual budget! But those profits are at risk.

Surveys indicate that annual harvests have recently declined.

Kelly Hopping: "The collectors themselves mostly attributed this to overharvesting, acknowledging that their own collection pressure was driving these declines."

And it doesn't help that it's difficult to regulate the harvest.

Daniel Winkler: "All these different political units have different policy. In the end, it is really down to county level, how it's implemented."

Climate change is also causing problems. You see, the fungus is more abundant in areas with long, cold winters, which are increasingly hard to come by.

Daniel Winkler: "For the rural economy, if there's a lot of loss, that would be devastating."

EDITOR'S NOTE: This video was originally published in March 2019.