Biologists mapping the human body have long assumed that every major kind of microscopic life inside us already had a place on the tree of life. The discovery of strange RNA-based entities called Obelisks, hiding in our mouths and guts, has shattered that confidence by revealing genetic structures that do not fit any familiar category of virus, bacterium, or viroid. Instead of tweaking the existing map, these findings suggest that the map itself is missing an entire class of biological actors living in and on humans.
Obelisks are tiny, rod-shaped strands of RNA that appear to infect the microbes that live in us rather than our own cells, yet they replicate, evolve, and spread in ways that look a lot like life. They are smaller than many viruses, lack the protein shells that usually define viral particles, and form their own distinct genetic group that current databases cannot place. I see them as a stress test for biology’s core definitions, forcing scientists to ask what it really means to be alive when new life forms in humans do not match the rules that textbooks still teach.
What exactly are Obelisks?
At the simplest level, an Obelisk is a microscopic genetic element made of ribonucleic acid, or RNA, that behaves like an infectious agent but refuses to fit neatly into any known category. Instead of carrying a full viral toolkit, these entities are compact strands that encode their own distinctive RNA structures and a small set of proteins, then hijack microbial machinery to copy themselves. Researchers describe them as rod-shaped, with a characteristic elongated architecture that sets them apart from the spherical or filamentous particles that dominate classical virology.
Current descriptions emphasize that an Obelisk is a microscopic genetic element composed of RNA, a type of infectious agent that has been found in human-associated microbes and in other environments, but whose replication still depends on host factors that are not fully understood. Unlike typical RNA viruses, they lack obvious sequence or structural similarity to known viral families, and unlike classic viroids, they encode proteins rather than relying solely on host enzymes. That combination of minimalism and novelty is why many scientists now treat Obelisks as a new class of biological entity rather than a quirky variant of something already cataloged.
A discovery hiding in plain sight
The most striking part of the Obelisk story is not just what they are, but where they were found. Instead of emerging from an exotic deep-sea vent or a remote cave, these entities surfaced inside routine datasets from human microbiomes, particularly in the gut and oral communities that have been sequenced intensively for more than a decade. When researchers reanalyzed human gut metatranscriptomic data, they noticed recurring RNA sequences that did not match any known virus, bacterium, or eukaryotic gene, and those sequences turned out to belong to a distinct group now labeled Obelisks.
One analysis of human microbiome samples reported that Obelisks form their own distinct phylogenetic group with no detectable sequence or structural similarity to previously described biological agents, even when compared against large viral and viroid databases. A related note on the same work highlighted that a team of scientists uncovered these entities while combing through human gut metatranscriptomic data, underscoring how much novelty can still be hiding in plain sight inside existing sequencing archives. The fact that such a fundamental surprise emerged from well-studied human samples suggests that our current computational filters may be discarding or mislabeling entire categories of life.
Smaller than viruses, stranger than viroids
Size alone does not define a life form, but it often hints at how it operates. Obelisks appear smaller than many viruses, yet they are more complex than the minimal RNA circles known as viroids that infect plants. Reports describe them as rod-shaped RNA bits that infest the microbes in our guts, with genomes that are compact but still capable of encoding proteins that help them replicate and persist. That puts them in a gray zone between the stripped-down genetic parasites that ride on host enzymes and the more autonomous viruses that package their own replication tools.
One early account described rod-shaped structures named Obelisks as “wildly weird” RNA bits that can still transmit instructions to cells despite lacking the typical viral architecture. Another overview of the human microbiome emphasized that these new visitors appear smaller than the viruses that usually dominate discussions of infection, and that their implications for humans remain unclear. Taken together, these details paint a picture of entities that are both minimal and sophisticated, operating at the edge of what biologists currently recognize as a self-propagating system.
How scientists stumbled onto a new life form
The path to Obelisks began with a simple question: what else is hiding in the vast sequencing data generated from human microbiomes? Researchers analyzing RNA from gut and oral samples noticed recurring patterns that did not align with any known organism, prompting a deeper search for virus-like agents that might have been overlooked. By filtering for small, circular or rod-like RNA genomes that encoded unusual proteins, they isolated a set of sequences that clustered together but did not match any existing viral or viroid families.
One group reported that new virus-like agents were identified in human gut and oral microbiotas, describing them as a new class of viral elements whose impact on health and biology remains unknown. Another account framed the work as Stanford University scientists discovering a new lifeform residing in the human microbiome, noting that the sequences they found had never before been identified or isolated. The convergence of these independent analyses, all pointing to the same family of RNA elements, strengthened the case that Obelisks are not artifacts but a genuine, previously unrecognized component of our inner ecosystem.
Living in our mouths, guts, and beyond
Once Obelisks were recognized as a distinct group, scientists began to look for them across different body sites and environments. The first wave of findings placed them squarely in the human microbiome, particularly in the oral cavity and the gut, where dense communities of bacteria provide a rich set of potential hosts. These entities appear to infect or associate with specific microbial species rather than human cells directly, which may explain why they went unnoticed in studies focused on human DNA or classical pathogens.Descriptions of their distribution note that Obelisks are living in you, hidden among the microbiome of our mouths and guts, and that they represent a fascinating work in progress for researchers trying to map their diversity. Beyond humans, a separate analysis found that Obelisks are recently discovered ribonucleic acid viroid-like elements that are widespread in the ocean, where they appear in diverse environments with bacteria likely acting as a replicative host. That broader ecological footprint suggests that what was first spotted in human microbiomes may be part of a much larger, planet-spanning network of RNA-based entities.
Do Obelisks count as life?
Whether Obelisks qualify as “alive” is not just a philosophical puzzle, it is a practical question that shapes how scientists study and regulate them. They replicate, mutate, and spread, which are hallmarks of life, yet they rely on host cells for many essential functions and lack the full metabolic machinery that organisms like bacteria possess. This puts them in the same conceptual neighborhood as viruses and viroids, which many biologists describe as existing at the edge of life rather than fully inside it.
Some researchers have framed Obelisks explicitly as a new type of life form living in the human body, while also acknowledging that they do not actually know yet how to classify them relative to viruses and other infectious agents. Another report described them as new biological entities called Obelisks in humans, potentially linked to microbial hosts, and emphasized that they challenge existing definitions of what counts as a distinct life form. For now, the safest position is to treat Obelisks as part of a broader continuum of replicating genetic systems, some of which fit neatly into current categories and others that force those categories to stretch.
Health risks, hidden allies, or something in between?
Whenever scientists uncover a new class of infectious agent inside the human body, the immediate question is whether it harms us. With Obelisks, the honest answer is that no one knows yet. They appear to target microbes rather than human cells, which could mean they influence health indirectly by reshaping the microbiome, but there is no clear evidence so far that they cause disease. It is equally plausible that they are neutral passengers or even beneficial partners that help maintain microbial balance.
Early coverage stressed that these new forms of life discovered inside human bodies have implications for humans that remain unclear, and that they may be hidden RNA carriers whose roles have yet to be mapped. A separate discussion of the microbiome noted that the health and biology of these new virus-like agents remain unknown, underscoring how early the field still is. Until researchers can link specific Obelisk variants to measurable changes in microbial communities or human symptoms, any claim about their danger or benefit remains unverified based on available sources.
Rewriting the map of the human microbiome
Even without clear health impacts, Obelisks already matter because they force a revision of how I think about the human microbiome. For years, the standard picture has been a three-way conversation among bacteria, viruses, and fungi, with occasional mentions of archaea and protozoa. The discovery of a whole class of RNA-based entities that interact with those microbes adds a new layer of complexity, suggesting that our inner ecosystem is structured not just by who is present, but by which genetic parasites and symbionts are riding on them.
One commentary on the findings argued that by identifying Obelisks, scientists can start to see the picture of the long-term evolution of viruses on Earth start to slowly emerge, because these entities may represent ancient branches of the viral world that persisted in microbial niches. Another analysis of ocean data showed that Obelisks are widespread in the ocean, with bacteria likely acting as a replicative host, which implies that similar RNA elements could be shaping microbial communities in many environments, not just inside humans. If that is true, then the human microbiome is just one local expression of a much larger network of RNA-based interactions that have been operating for a very long time.
Why this matters for the future of biology
Obelisks are not just a curiosity, they are a stress test for the tools and assumptions that modern biology relies on. Their discovery depended on high-throughput sequencing and sophisticated computational filters, yet they still slipped through earlier analyses because they did not resemble anything in existing reference databases. That suggests that other, equally strange entities may be hiding in current datasets, waiting for someone to ask a slightly different question or apply a more flexible search strategy.One video discussion of the topic framed Obelisks as never before seen viral organisms found inside our bodies, highlighting how unusual and difficult to explain they are using standard categories. A podcast episode about the same subject emphasized that since we cannot easily culture or visualize them, they remain a fascinating work in progress that will require new experimental methods. As researchers refine those methods, I expect Obelisks to become a test case for how biology integrates genuinely new forms of life into its conceptual framework, and for how medicine decides which of those forms matter for human health.
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