The fictional fungus in “The Last of Us” touched a collective nerve. When it comes to mushrooms, we just can’t keep our cool.It’s grim, but in every post-apocalyptic story line, I wait for the moment when the characters float their theories about how the world fell apart, hoping to glean something useful.In HBO’s series “The Last of Us,” survivors of a global pandemic live in harsh, government-controlled quarantine zones to evade a parasitic fungus that turns them into zombies. Joel, a smuggler in what remains of Boston, believes that the ophiocordyceps mutation was delivered through the food system — contaminated batches of globally shipped flour or sugar spread the disease too quickly and efficiently for any kind of recall. Over the course of a long weekend, humanity was wrecked.The setup sounds pretty conventional for the zombie-thriller genre, but since the series premiered in January, the response has been a bit sweaty — panicked, even. Mycologists, fungal biologists and other mushroom-world experts have been called on, over and over, to assure us that while cordyceps species that zombify insects are real, a cordyceps mutation that thrives in humans is pure fiction.What got us so rattled?The fictional cordyceps mutation in HBO’s zombie-thriller series “The Last of Us” takes fear of fungus to the extreme.Warner MediaPaul Stamets, one of the country’s best-known mycologists, enjoyed the first two episodes of the show, but posted afterward on Facebook to emphasize the fact that no, cordyceps really aren’t capable of all that. “It is natural for humans to fear that which is powerful, but mysterious and misunderstood,” he wrote, wondering if the show played on our deep-seated fear of mushrooms.Inside the Dystopian World of ‘The Last of Us’The post-apocalyptic video game that inspired the TV series “The Last of Us” won over players with its photorealistic animation and a morally complex story.Game Review: “I found it hard to get past what it embraces with a depressing sameness, particularly its handling of its female characters,” our critic wrote of “The Last of Us” in 2013.‘Left Behind’: “The Last of Us: Left Behind,” a prologue designed to be played in a single sitting, was an unexpected hit in 2014.2020 Sequel: “The Last of Us Part II,” a tale of entrenched tribalism in a world undone by a pandemic, took a darker and unpredictable tone that left critics in awe.Playing the Game: Two Times reporters spent weeks playing the sequel in the run-up to its release. These were their first impressions.There are around 1.5 million species of fungi, a kingdom that is neither plant nor animal, and they’re some of the strangest and most marvelous life-forms on the planet, both feared and revered. But our relationship with mushrooms, particularly in the West, can be fraught — and not just because misidentifying one might be dangerous.In nature, mushrooms happily appear under the grossest and most fractious circumstances, when little else will. They can signal death, thriving in damp, dark rot, blooming in decomposition and nimbly decaying organic matter. Nevermind that this process is vital and regenerative (and, witnessed in a time-lapse, weirdly beautiful), it really freaks us out.When the artist Jae Rhim Lee wondered if it was possible for us to make a collective cultural shift, to approach death and its rituals differently, and to make smaller environmental impacts when we die, she designed a burial suit seeded with mushrooms. Nothing could be more natural — or more horrifyingly taboo — than, instead of eating mushrooms, inviting the mushrooms to eat us.Bioluminescent mushrooms, seen here in Gangwon Province, South Korea, glow in the dark.Video by Imazins / Getty ImagesMushrooms have a way of making us consider the things we prefer to avoid. Though this hasn’t stopped us from eating them — mushrooms are an ancient food source.The “stoned ape theory,” which imagines fungus as central to our evolution, was animated in Louie Schwartzberg’s terrifically pro-mushroom documentary, “Fantastic Fungi.” One scene shows how early humans might have eaten mushrooms, including psychedelic ones, off animal dung as they tracked prey across the savanna, then collectively tripped their way toward language, weaponry, music and more.Small, round buttons are the most cozy, familiar and recognizable of our edible mushrooms now, but there are hundreds of varieties we can eat (without tripping). In the pockets of wilderness around my home in Los Angeles, you might find brownish-orange candy caps, wild, yellowish frills of chanterelles and clusters of long-gilled oyster mushrooms. After rain, in the shady nooks of my own backyard, I see shaggy parasols pop up from time to time, as if by magic.In “The Last of Us” a warming climate weaponizes mushrooms against humans — a global disaster of our own making. But in reality, if you scratch just below the surface of our fear, you’ll find quite the opposite: an almost unreasonable expectation that mushrooms will rescue us, clean up our messes, do our dirty work and reverse all of the damage we’re doing to the earth. It’s true that there are species capable of breaking down oils in saltwater, absorbing radiation and cleaning toxins from the soil, though it’s also true that they might have better things to do.A handful of shaggy parasols, a common mushroom with a tousled cap.Deagostini Picture Library / Getty ImagesMushrooms are the fruiting bodies of the mycelium, rootlike threads that connect underground in a vast mycorrhizal matrix so complex, intelligent and essential, Mr. Stamets has called it “the neurological network of nature.”That material, which also stores large amounts of carbon underground and can help plant life survive drought and other stress, is being used to develop alternatives to leathers, plastics, packaging and building materials. (Adidas made a concept shoe using a mycelium-based material last year, which led the company to discuss its “journey to create a more sustainable world.”)Lately, we expect mushrooms to save us, too. The zealous interest in adaptogenic mushrooms — fungi species used medicinally for centuries in China and other parts of Asia — has created an international market for lion’s mane, reishi, chaga and cordyceps. We turn to mushrooms to ease our anxiety, to help us focus, to make us happier and more open-minded, to make us horny, to make our skin glow, to enhance our memory, to get us to sleep.Mushrooms are magnificent. But maybe anxiety over a fictional fungus reflects a flickering awareness that we are, in fact, asking a bit too much of them.Follow New York Times Cooking on Instagram, Facebook, YouTube, TikTok and Pinterest. Get regular updates from New York Times Cooking, with recipe suggestions, cooking tips and shopping advice. More