Can the zombie fungus from The Last of Us happen in real life? Details explored

When The Last of Us first appeared on screens, it wasn't only the story that had viewers in its clutches — it was the horrifying possibility: What if this really did happen? A world where a fungal mutation commandeers the human brain, destroys consciousness, and turns humans into vicious, fungus-controlled hosts? It's repulsive. But simultaneously, it sort of felt all too true. And for good reason — the idea is rooted in true scientific reality.

The developers of The Last of Us didn't conjure the idea from nothing. The series is inspired by an actual parasitic fungus, Ophiocordyceps unilateralis, which infects wild insects. The icky part? This fungus takes over its host's mind. But before everyone freaks out about mushroom zombies, the fungal infection depicted in "The Last of Us" is highly unlikely to occur in real life. Let's take a look at the science behind it all — and whether there's any actual danger of this fiction becoming reality.

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Where does "The Last of Us" zombie fungus come from?

The fungal plague that devours human society in The Last of Us results from a mutation of the parasitic fungus Cordyceps, spread through bites, spores, and contact, killing its host at gruesome rates. Infected humans become insane and die as the fungus grows inside them, finally culminating in misshapen fungal growths from their mouths.

As crazy as it sounds, this is something that has its foundation in real biology. The representation of Cordyceps by the show draws inspiration from a real fungus named Ophiocordyceps unilateralis. It mainly occurs in rainforests, which are tropical, and infects ants rather than humans and takes control over their nervous systems. It forces the ant to crawl up to a lofty position, bite, and die, and the fungus then grows out of the ant's body and releases spores. If that sounds familiar, it's because it perfectly duplicates what happens in the first episodes of the show.

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Could Cordyceps actually infect humans?

Here's the reassuring part: No, Cordyceps can't infect humans. So far, the fungus has learned to infect only insects, not just any insect, but certain species of ants. Its infection mechanism is very particular and does not extend to humans. Our bodies, immune systems, and brain chemistry are very different from ants, so a jump like this in hosts is very unlikely.

Secondly, human body heat is a major obstacle. Most fungi, even the Cordyceps, can't survive for long at 98.6°F (37°C), which is our usual internal body temperature. In The Last of Us, the television show adaptation's version of the fungus mutates due to global warming, allowing it to resist higher temperatures and transfer to humans. That could be an awesome plot twist, but no real evidence exists that such a mutation is realistically possible.

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Are there fungi that can hurt us?

Although Cordyceps itself will not trigger a zombie apocalypse, the general idea of dangerous fungi is not entirely fiction. Some fungal infections are indeed on the rise. One of the largest concerns in recent years has been Candida auris, a fungus that is resistant to drugs and can infect hospitals, posing serious health risks, especially for those with weakened immune systems.

Unlike in The Last of Us, these infections aren't spread theatrically, via bites. They're also treatable in most cases, albeit with resistant strains beginning to be a problem. But they certainly leave one considering whether climate change, overuse of antifungals, and global travel are influencing fungal evolution in the real world.

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Would global warming make fungi more deadly?

The Last of Us implies that warmer temperatures were the stimulus that allowed the Cordyceps-like fungus to evolve and thrive in humans. Interestingly, scientists do acknowledge that global warming is partially to blame for fungal adaptation. As the environment warms, fungi are slowly adapting to better tolerate heat, which potentially brings some species closer to being able to survive in the human system.

But adaptation is a slow process. It doesn’t happen overnight, or even in a decade. The kind of radical transformation seen in The Last of Us — where a fungus not only survives in humans but takes over their nervous systems — would require an evolutionary leap we’ve never seen before. It’s speculative fiction at its core, not an imminent scientific threat.

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Mind control: Real in ants, not in humans

Perhaps the most unnerving aspect of The Last of Us is the way the fungus infects its human hosts — physically, but also psychologically. Infected characters lose all traces of personality and are instead controlled by the fungus itself. Cordyceps does infect and command ants in the real world, but this "mind control" isn't like that in our current comprehension of it.

The fungus changes the way muscles are controlled and the behavior of the ant, apparently by releasing chemicals that affect the motor functions of the ant. It doesn't "think," and the ant itself isn't even aware of this. Transposing the same process to human brains is a gigantic leap. Human thought processes are far more complex, and there is no suggestion that any fungus could defeat them in the same way.

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So, can the zombie fungus of The Last of Us actually happen in real life? Based on everything we know now, no. Not yet, and not ever soon. The science behind the show is real, but it only occurs in insects, and the leap to infection in humans is a hurdle that today's fungi simply can't overcome. The show's narration is interesting and terrifying, yet it is science fiction.

All of that aside, the heightened interest in fungi, thanks to The Last of Us has presented a chance to have more dialogue about real-world fungal threats. Researchers are taking note of how fungi evolve, especially to ecological stresses. There isn't a Cordyceps apocalypse that's going to end the world, but we're learning about the ways that fungi behave — and that may not be all bad.

Also read: What to expect from The Last of Us Season 2? Pedro Pascal reveals the answer and more