This is the newest and hottest item of speculation in China right now, guess how much it is worth: 300,000 RMB per kilogram (for your reference, I just checked the live gold price and it was about 174,400 RMB per kilo). This "worm grass" is worth 1.7 times the price of gold.
But what the heck is it?
I turned to my good friend Wikipedia:
"Caterpillar fungus (Cordyceps sinensis) is a species of parasitic fungus that grows on insect larvae from the genus Thitarodes. Its name is Chinese (dong chong xia cao 冬虫夏草) means "winter worm, summer grass".
"...The fungus invades the body of the Thitarodes caterpillars, eventually killing and mummifying it. The dark brown to black fruition body (or mushroom) emerges from the ground in spring or early summer..."
"...is highly prized by practitioners of Tibetan medicine, Chinese medicine and traditional herbal Fold medicines, in which it is used as an aphrodisiac and as a treatment for a variety of ailments, from fatigue to cancer. It is being regarded as having an excellent balance of yin and yang..."
I guess the magic word is "aphrodisiac" then.
Unfortunately, a trend like this in China will only lead to two things: one, the market will get flooded with fake worm grass and sooner or later someone is going to get really sick; two, the suppliers will just harvest the plant like crazy thereby disturbing the ecosystem of the Tibetan highlands, the place where worm grass is found. Apparently this is already happening, the overall production volume of worm grass is now 3.5% of that 25 years ago, and there is 61500 square kilometers of soil erosion around the Yarlung Tsangpo River (Brahmaputra River's upstream in Tibet).