A deadly fungus once blamed for killing tomb raiders might actually help save lives—at least, if you’re a leukemia cell on the receiving end.

Researchers at the University of Pennsylvania just turned Aspergillus flavus, the mold long linked to the so-called “pharaoh’s curse,” into a cancer-fighting weapon. In a new study published in Nature Chemical Biology, scientists showed that compounds extracted from the toxic fungus could be just as effective at killing leukemia cells as FDA-approved chemo drugs.

If the name sounds familiar, that’s because A. flavus has a morbid reputation. It’s been suspected in the deaths of archaeologists who opened King Tut’s tomb in the 1920s and again in the 1970s when 10 out of 12 researchers died after entering Poland’s Casimir IV tomb. At the time, the deaths were chalked up to ancient curses. In reality, they may have just inhaled something a lot more literal—and fungal.

Now, researchers are putting that same spore to use. “Fungi gave us penicillin,” said Sherry Gao, a professor at Penn and senior author on the study. “These results show that many more medicines derived from natural products remain to be found.” Her team isolated four never-before-seen molecules from A. flavus, calling them asperigimycins. They’re part of a class of compounds called RiPPs, which are rare in fungi and notoriously hard to study—mainly because no one was looking closely until now.

This Ancient ‘Pharaoh’s Curse’ Might Be the Future of Cancer Treatment

Even in their raw form, two of the asperigimycins knocked out leukemia cells in lab tests. One souped-up version, tweaked with a fatty acid found in royal jelly, worked just as well as traditional leukemia treatments like cytarabine. The team also discovered that a human gene, SLC46A3, acts like a gateway, helping the drug sneak inside cancer cells, a small clue that could help improve delivery of future treatments.

As for side effects? So far, the asperigimycins don’t seem to mess with other healthy cells, which is rare for cancer meds. They work by disrupting microtubules, those tiny scaffolding-like structures cancer cells need to divide and multiply.

The next step is testing in animals and, hopefully, clinical trials. Until then, it’s another reminder that nature, especially the parts of it that used to terrify us, might still be hiding some of our best medicine.

“It’s up to us to uncover its secrets,” Gao said. And sometimes, those secrets are buried in tomb dust.