That’s the Cordyceps fungus, a parasite that takes control of the body of the host and uses that much more mobile body (well, compared to a fungus) to propagate itself into the world. (Fungus have no feet, you know.)
The first time I saw that video, I figured that there must be an equivalent fungus for humans. I realize they show no animals other than insects as living relics to the power of the Cordyceps, but what if there were such a fungus? What if it adapted to humanity, found some way to breach the blood-brain barrier, and had an incubation time of a few days or even weeks? What if the makers of the documentary didn’t want to panic the general populace? What if tourists traveling through rain forests were infected by chance?
The fungus wants to be in the best place to spread its spores. What would be better than malls and airports?
Of course, the problem there (for the fungus, not us) is that a motionless person with a spore growing out of their head would be pretty noticeable.
Which is why the successful fungus would be those whose growths looked most like human hair, mimicking a bouffant or a mohawk.
Still, eventually these people-no-longer would be noticed.
The other variety to provide a threat to humanity? The fungus that directed people to go to the backyard of their suburban house rather than the crowded places. Here, undisturbed, the Cordyceps would grow, protected from discovery by privacy fences.
But those privacy fences wouldn’t protect from the onslaught of spores once the Cordyceps was ripe.
Whole neighborhoods, wiped out. Suburbia devastated.
People would flee to the cities where, at least, you are forced by proximity to keep an eye on your neighbors.
And that’s how I create a story idea.
Or at least that’s what the fungus wants you to think.