Yartsa gunbu (summer grass-winter worm) is a fungus that parasitizes moth larvae by devouring them from the inside-out and sprouting from their exoskeleton. It has been used for centuries by Tibetan and Chinese doctors to “improve breathing, metabolism, sexual function, mental clarity, and more.”
Demand for the mushroom has skyrocketed, according to Epoch Times:
Tibet has enjoyed a vigorous caterpillar fungus trade with China for centuries, but in recent decades prices have skyrocketed. A pound of yartsa gunbu was less than two dollars in the 1970s, and close to $100 in the 1990s. Today, a pound of high quality specimens could sell for as much as $40,000 or more. Total revenue from yartsa gunbu comes to about a $1 billion a year.
Ecologist and mushroom specialist Daniel Winkler says, “I know Chinese people whose friends are willing to spend half of their income on this, because they feel like, ‘Well, I’m getting old. I’m falling apart. This buys me life.’ That’s why people are willing to pay this incredible amount.”