[This blog post comes to you from author Rebecca L. Johnson.]

A common question I get from students when I give school presentations about my books is “Where do you get your ideas?” They laugh when I tell them that the inspiration for my latest book, Zombie Makers: True Stories of Nature’s Undead, was flies. Dead flies, to be precise.

It all began when I was reading an article in a science journal that referenced a fungus, Entomophthora muscae, that parasitizes houseflies, the types that plague us outdoors, buzz around barn yards, and sneak into houses, especially attics. The infection begins when a microscopic fungal spore lands on a fly, sprouts to penetrate the skin, and then spreads like some Hollywood alien life form throughout the fly’s body, eventually growing into its brain. That’s when things really get interesting. Thanks to a cocktail of chemicals it secretes, the fungus takes over the fly’s brain, turning it into a real-life zombie and controlling its movements like a puppeteer. With the fungus pulling the strings, so to speak, the fly climbs to a high place and adopts a spread-eagle stance. And so it remains, stock still, until the fungus kills it and produces thousands of spores that shoot out of the fly’s forlorn carcass. The article mentioned that a ring of spores can sometimes be seen around infected flies that meet their end on window panes.

Knowing that the attic in my old house is typically invaded by houseflies in summer, I went up to have a look. Lo and behold, there they were: at least half a dozen fly corpses plastered to the glass and surrounded by halos of what looked like a fine white powder. Spores. Dead flies. Mind control. I had zombies and zombie makers under my own roof. I was hooked at that moment and as I began to dig into the subject and talk to scientists who study different parasites able to control their hosts in similarly astonishing ways, Zombie Makers was born.

I’ve found that few people, kids or adults, are neutral about zombie-making parasites. Rather, they tend to fall into two groups: those who are completely grossed out by the whole idea and those who are absolutely enthralled that something as tiny as a fungal spore or a microscopic worm or even a virus particle can take control of a much larger living thing and turn it into a zombie, all so that the zombie maker can successfully reproduce and continue its life cycle. It’s probably fairly obvious that I belong to the latter group.

But I’ve also noticed that when I talk about nature’s zombie-makers—or worse yet, show pictures from the book—even those folks who recoil can’t stop listening and looking. They’re like people who cover their faces at horror movies but peek through their fingers, or the spectators who lined the streets of my hometown last Halloween during the annual “zombie walk.” It was the first time I’d participated (I was finishing up the writing of Zombie Makers, so it seemed appropriate). I went as Alice in Wonderland and my husband as the Mad Hatter. Along with a thousand other lurching, groaning zombies, we stumbled through the downtown to the delight of the onlookers who were transfixed by the deliciously creepy, skin-crawling fun of it all.