On the hit zombie TV show "The Last of Us", the cordyceps fungus turns people into "super-strong killing machines", said Bloomberg.
But in traditional Chinese medicine the chilli-shaped fungi are "prized as a panacea" and "an aphrodisiac" – so much so that one species found throughout the Himalayas, cordyceps sinensis, is "worth four times its weight in gold". But the booming demand for so-called "Himalayan Viagra" is taking its toll on a vulnerable region.
Since Nepal legalised trade in the fungi, known by the Tibetan name "yartsa", in 2001, they have become a "coveted gift" in China, South Korea and Japan.
Researchers estimate that the global market could be worth as much as $11 billion (£8.7 billion) a year.
The world's "most highly prized parasite" is an important source of income in the extremely poor region, said Oryx Journal. But its harvest and sale is "often illegal and unsustainable". In 2020, the non-profit International Union for Conservation of Nature warned that yartsa numbers had declined by at least 30% over 15 years.
The increasing demand is having "a huge ecological impact" on the region, said New Scientist. Hunting for the fungus has been linked to increased soil erosion, deforestation and the pollution of rivers. It's dangerous, too. In 2023, more people died hunting yartsa than "summiting Mount Everest". The trade has also been linked to child labour, smuggling and turf-war violence.
"Yartsa needs regulation and we need to shore up our borders," said Rajendra Bajgain, a member of Nepal's House of Representatives. "It's out of control." | 
