Back in January, I wrote about the psychedelic mushroom that makes people from all over the world hallucinate the same thing. Scientists call them Lilliputian hallucinations, a phenomenon in which people see tiny little people, almost like something out of Gulliver’s Travels. The Adult Swim animated series Common Side Effects features a fictional mushroom that induces similar hallucinations of odd pocket-sized fantasy people.

Surely this has to be the work of some known psychedelic compound, right? According to new research, it doesn’t seem to contain any known psychedelic at all, which makes very little sense and has scientists genuinely puzzled.

Lanmaoa asiatica is a wild mushroom sold in markets throughout southwestern China. According to reports collected from hospitals in China’s Yunnan Province, people who eat the mushroom undercooked frequently experience vivid hallucinations involving miniature people, elves, or tiny human-like figures. No matter the nationality or cultural background of the person taking it, across the board, everyone seemed to hallucinate roughly the same little people.

To figure out what was happening, researchers led by University of Utah biologist Colin Domnauer sequenced the genomes of dozens of mushrooms from the broader Lanmaoa family. Their findings, published in the journal Mycologia, ruled out the obvious and seemingly only explanation for the cause of the hallucinations, that being that they contain any kind of known hallucinogens.

The mushroom lacks the genetic pathways needed to produce psilocybin, the compound that puts the magic in magic mushrooms. It also lacks ibotenic acid, the psychoactive ingredient from the fly agaric mushroom. That’s the iconic Super Mario-like mushroom with a milky white stalk and a bulbous red cap covered in white dots.

The results match previous chemical analysis, which also couldn’t identify any known hallucinogenic compound that could produce any hallucination, let alone one that lets people from all over the world experience just about the same kind of hallucination.

Psychedelics generally produce hallucinations that are specific to a person’s life experiences, environment, and mental state. L. asiatica doesn’t care who you are as an individual. It’s going to give you almost the same experience as anybody else gets while under the influence.

All researchers have are theories, with the current leading theory being that there has to be an entirely unknown compound or some kind of biochemical pathway that researchers just haven’t discovered yet. If true, then we may be on the verge of finding a whole new category of psychoactive chemistry.