How Close Are We to The Last of Us? What Real Science Says About Mind-Controlling Fungi

Now that the dust has settled on that split-the-room Season 2 finale, let’s talk about the actual fungus at the core of The Last of Us. The show borrows its nightmare from the 2013 game and its 2020 sequel, which dropped right as the real world was dealing with COVID. Great timing for TV tension, less great for scientific plausibility. So how close does the series get to reality? Short version: it’s inspired by real biology, then takes a long walk into fiction.

What the show tells us

Humanity gets wrecked by a mutated strain of Cordyceps (Ophiocordyceps unilateralis), a parasitic fungus that hijacks brains and turns people into bite-happy drones whose only job is to spread the infection. The lore splits the infected into stages — Runners, Stalkers, Clickers, and Bloaters — each level more wrecked than the last.

Transmission evolves across the series. In Season 1, the outbreak is tied to contaminated crops, then person-to-person via bites, saliva, and other bodily fluids. In Season 2, the fungus goes airborne and people get sick by breathing in spores. That change becomes a major story engine and the source of some gnarly set pieces — and yes, the finale that has people arguing.

The real Cordyceps: nasty, fascinating, and (so far) not our problem

Here’s what the fungus actually does in nature. Cordyceps is the infamous zombie-ant fungus. It infects arthropods — ants, spiders, insects — not humans. The spores latch on, chew through an exoskeleton, and seize motor control. The host climbs to a high spot — branches, bushes — where sunlight and airflow help the fungus breed. After the insect dies, a stalk sprouts, mushrooms out of its head, and showers new spores onto the next victims. Under the soil, a fungal network (mycelium) keeps the operation going.

That behavior is real. Translating it to humans is where the fiction kicks in.

"Very few fungi or mold spread person-to-person, so a fungal pandemic is not too likely," says Dr. Scott Roberts, an infectious disease specialist at Yale School of Medicine. He adds, "There are millions of different fungal and mold species out in nature that don’t cause any sort of infection in humans, and this is one of them. A Cordyceps that infects one species of ant cannot even infect other species of ants."

Why the science breaks (and where it bends)

• Human bodies run hot: average 98.6°F. Most fungi struggle above ~94°F, which is why a mycologist freaks out in the show when the fungus supposedly adapts. That heat barrier is a huge, built-in defense.
• Fungi don’t spread like viruses. As Dr. Roberts puts it, viruses are engineered by evolution for person-to-person spread — sneeze once, infect a room. Fungal infections usually come from the environment (inhaling spores, open wounds), and once someone’s infected, passing it to another person is exceedingly rare.
• Food-borne outbreaks? More of a bacteria thing. E. coli and Salmonella love that route. Fungi, not so much — at least at the temperatures we live in right now.
• Our nervous system is too complex to puppet. Insects have simpler nerve clusters (ganglia) that are easier to hijack. Human brains are another league entirely.
• Psychoactive mushrooms can tweak perception (hello, psilocybin), but the effects fade and they’re not contagious diseases.
• Climate change is the wild card. A hotter planet could push some fungi to adapt to higher temps, inching closer to our body heat. The show leans on that idea. In the real world, Candida auris already thrives in warmer settings, spreads person-to-person, and is notoriously hard to treat — which is exactly why it alarms doctors. Still, C. auris won’t turn anyone into a rage zombie; it’s a serious medical threat, not a mind-control parasite. Other heat-adapting troublemakers like Aspergillus and Cryptococcus neoformans can cause dangerous lung and systemic infections, but not behavior rewrites.
• Antibiotics overuse makes fungal problems more likely. Knock out your beneficial bacteria, and fungi can take over. As Roberts says, antibiotics are a big risk factor for fungal and yeast infections because they wipe out the good and the bad.

The timeline twist (and why it matters)

The games put the outbreak in 2013 and Joel and Ellie’s journey in 2033. The HBO series rewinds all of that by a decade: outbreak in 2003, aftermath in 2023 — a deliberate move to make it feel contemporary alongside COVID. The trade-off is scientific wiggle room. From 2025 to 2033, there probably isn’t enough time for Cordyceps to evolve the thermal tolerance and human-specific hacks the show leans on. Push the clock out to, say, 3033 and sure, after centuries of selection pressure and a hotter Earth, you can start to imagine fungi adapting in ways that are scarier for us. Still not brain-hacking, but more plausible infections.

So where does that leave the show’s big swing?

In a smart spot for storytelling: rooted in real fungal behavior, then magnified for drama. The Cordyceps Brain Infection as depicted — mind control, fast human-to-human spread, airborne spore clouds that take down cities — is next to impossible in 2025. Could fungi become a bigger, broader threat over centuries thanks to climate change and our antibiotic habits? Yes. Would that threat look like Clickers and Bloaters? No.

Bottom line: The Last of Us uses sci-fi pandemic horror to get us thinking about very real fungal risks and how little attention they get. It’s compelling TV that borrows true biology, then sprints past the science for effect — and that Season 2 finale made sure we’re still arguing about it.