People in communities thousands of miles apart have described the same strange experience after eating a mysterious mushroom: vivid visions of tiny humans moving through and interacting with the physical world around them. Known as Lilliputian hallucinations—a reference to the 6-inch-tall inhabitants of "Gulliver's Travels"—the phenomenon has long been thought to stem from cultural influences rather than biology.

A new study suggests otherwise.

Using DNA sequencing, University of Utah (U) researchers confirmed that a single mushroom species, Lanmaoa asiatica, is responsible for these hallucinations in Southwest China and the northern Philippines.

They also discovered that the mushroom contains none of the psychoactive compounds known to science, including psilocybin. Instead, the findings point to an entirely new hallucinogenic compound that could offer new insights into neurological disease and how the brain shapes perception and consciousness.

Colin Domnauer, a doctoral student at the U, and Bryn Dentinger, a mycologist at the U and the Natural History Museum of Utah, coauthored the study that was published June 5, 2026, in the journal Mycologia.

Domnauer spoke to @theU about the Lilliputian mushroom, the decades-long mystery behind it and the implications of a new hallucinogenic compound.

People have reported Lilliputian hallucinations for nearly a century, yet the mushroom behind them remained a mystery. How did you finally identify it?
In 1934, Western scientists first heard reports from Papua New Guinea of people hallucinating tiny humans after eating wild mushrooms, a phenomenon they dubbed "mushroom madness."

Anthropologists and mycologists went to Papua New Guinea in the 1950s and 1960s, narrowing the culprit to a few species in the Boletaceae (bolete) family. They did some chemical analyses but couldn't find any psychoactive components. They even sent samples to Albert Hoffman, who first isolated psilocybin and discovered LSD, but even he couldn't find an active compound.

Eventually, they concluded that maybe these mushrooms weren't bioactive at all—maybe this was all just a sociocultural phenomenon. So, research really ended in the 1960s.

Decades later, in the 1990s, there were reports from Yunnan in Southwest China of a very similar phenomenon after people ate bolete mushrooms. The species wasn't clear, but mycologists suggested that it might be L. asiatica, then a newly described mushroom.

In 2024, I heard similar accounts from an Indigenous community in the Philippines' remote Northern Cordillera region who were consuming a wild mushroom called "Sedesdem" that, according to local knowledge, occasionally caused visions of little people. Known as the "Nonda" in Papua New Guinea and "Jian shou qing" in Yunnan, it's a culturally important edible mushroom that, if undercooked, would produce the hallucinations.

That was the third independent case linking a wild mushroom to visions of little people.

I went to Yunnan and the Philippines, spoke with locals and collected L. asiatica and as many specimens in the Lanmaoa genus as I could find for DNA sequencing. That was the first scientific survey of Northern Philippine fungi that had ever been done.

It turns out that China's Jian shou qing and the Philippines' Sedesdem were both L. asiatica—which was very surprising because at the time, we thought L. asiatica only occurred in China. Unfortunately, when Dentinger traveled to Papua New Guinea, unusually dry conditions prevented us from collecting specimens for comparison.

Now, three completely independent cultures have reported the same specific type of hallucination, and two cases are attributed to the same DNA-verified mushroom species. That indicates that these bizarre psychological effects aren't cultural manifestations or coincidences—they must have a shared underlying chemical and neurological basis.

What makes the hallucinations so unusual?
People pretty much always report seeing dozens or hundreds of little people, about 3 to 30 centimeters tall (1 to 12 inches), in incredible detail, like they're actually there. About 90% of people describe them as little elves or clowns or other fairy-like figures dressed in colorful clothes.

What's fascinating is they interact with the physical world using the laws of physics that govern us. They're not walking through walls or anything. They're falling off the edge of tables, walking around objects. One person told me that while they were eating soup, the little people were jumping off their spoon into the bowl and swimming around. As they scooped a bite, the little people remained in their mouth.

Why do you think L. asiatica has different compounds than other psychedelic mushrooms?
We searched inside the mushroom, both chemically and genetically, for the presence of any known psychoactive mushroom compounds, and we found absolutely no trace of them. This wasn't too surprising, as the strange symptoms are quite unlike any known drug.

Why is the prospect of a new psychoactive compound exciting?
Lilliputian hallucinations predate this mushroom. There are myths about tiny people in pretty much every culture's folklore. People have also reported these hallucinations from alcohol withdrawal, dementia, macular degeneration and other neurological conditions. So, it seems like this phenomenon is fundamental to how the human mind and brain work, but we don't know what causes it or how to treat it.

That's what makes this mushroom different—it reliably produces this effect, whereas those conditions very rarely trigger it.

If L. asiatica has some compound that can reliably induce these hallucinations, it could be a very powerful tool for understanding the mechanisms behind them.

Our next step is to isolate and identify that new psychedelic compound.

Your study is the first comprehensive genomic analysis of all Lanmaoa species. What else did you find?
I wanted to understand the diversity and evolution of this whole Lanmaoa group of mushrooms. So, we collected specimens from around the globe and sequenced the genomes of 53 specimens from the wild and fungarium collections. We found that there were 17 species in this group, including four new species, two of which came from existing U.S. collections.

Our analysis showed that L. asiatica is the only psychoactive species in this genus. Now we're building an evolutionary map to understand how this trait evolved and whether related species produce similar compounds.

I think one of the most exciting findings is that there was so much hidden diversity sitting in museum collections that we never would have recognized without DNA sequencing. It reveals how much biological novelty is hiding in plain sight, waiting to be discovered.

Fungi are extremely underexplored. Why do you think it's important to expand our biodiversity knowledge?
We're just scratching the surface of the fungal kingdom. Look at penicillin—that was isolated from a fungus and was probably the most revolutionary medicine of the last century. Who knows what other miracle medicines or revolutionary understandings we'll find by exploring nature.