Resident Evil Mold and the Real World Zombie-Fungus

There is some truth to be found behind the mold in Resident Evil Biohazard and Village. Ophiocordyceps unilateralis is a real-world fungus that infects ants and controls them. This has earned O. unilateralis the nickname Zombie-Ant Fungus. With this is mind, suddenly, the terrors of Resident Evil's mold are not far off from reality.

Resident Evil Mold and the Real World Zombie-Fungus

It has been over a year since the release of Resident Evil: Village. After all of this time, it is still a topic of conversation among survival horror fans. The soon-to-release story DLC is merely fuel to a fire still burning. There is a draw to the blood and mold of a fictional world overturned by the Umbrella Corps. Something calls to it and refuses to let us go. Like a compulsion. Like a fungus festering.

The latest installment to the long-loved franchise brought about a myriad of new lore additions: vampires, lycans, and witchcraft to name a few. There was also a nearly universal tinge of excitement with the reappearance of inventory management similar to RE4 and a prominent return of Chris Redfield. All of that aside, it was also clear that two aspects of Resident Evil: Biohazard had been carried through to this direct sequel: Ethan Winters and the mold.

The Mold Grows Everywhere

The mold became a prominent facet of the Resident Evil story in the seventh mainline game. The franchise is most commonly associated with viruses, specifically the T-Virus, as its microbial adversary, but Biohazard took a pivot from virology to mycology. Instead of a virus infecting and causing zombification or a vast array of mutations in victims, the mold took over a host organism, growing over and within, and eventually control them. These mold-controlled monstrosities were aptly named the molded.

Molded crawling up a stairwell, always hunting Ethan.

Molded crawling up a stairwell, always hunting Ethan.

Mold, within the context of the Resident Evil universe, is very similar to the infection from The Last of Us. The key difference between these two worlds, from a scientific standpoint, is that the world of The Last of Us has a lot more variety of infected individuals. Could such a fungus mutate and could that lead to drastically different creature types? Also, it is possible such large-scale mutations could occur due to large genetic variations in the host? Many things to ponder.

There is one primary question to consider first: could a mold actually engulf and create some level of mental control over the host? Now, the games use a virus, but many of the tell-tale signs of infection are existing side effects from bacterial infections. Though not something quite experienced or encountered in reality, a single infectious agent could very possibly encompass a variety of different side effects already known and these additive effects could result in the general zombies found throughout the Resident Evil universe. But, that is a much larger topic.

Real World Zombie-Fungus

Before delving into a figurative smorgasbord of theoretical possibilities, the first place to look for answers is in nature. Are there any already existing, naturally occurring processes that this can be linked to? This is especially important when trying to answer a question in the exceedingly complex and much more ethically and experimentally difficult to work with higher eukaryotes, the human. Well, this may sound strange, but there is an existing case that is transferable to the question posed above. There is a real fungus that acts in a much similar way as the mold in Resident Evil does, but only to insects. At least, so far as has been found.

Fungus growing on a decaying log.

Fungus growing on a decaying log.

This peculiar fungus is named Ophiocordyceps unilateralis. Playfully, it is referred to as the zombie-ant fungus. First discovered in 1895 by the British natural scientist Alfred Russell Wallace, O. unilateralis has been growing quite rapidly as an organism of interest in modern mycology, microbiology, and biochemistry studies. How O. unilateralis operates may sound startlingly familiar for the brave souls that have traversed the horrors of Biohazard.

Initial Fungus Infection

An ant is out and about, scavenging for food or carrying dirt out of the newest expansion to the nest. All work and no play at the behest of the queen. While going about its ant-ly duties, it fails to notice its metasoma, or that extra round abdomen on the back of the insect, rubbing against a blade of grass. And why would it notice this? There is nothing out of the ordinary or uncommon about this. Most people do not explicitly notice every time their elbow grazes a wall, catches a shower curtain, or bumps into a stranger on the subway unless it causes a sudden startle or pain. The problem with this ant not thinking anything of this is that it picked up as little as a single O. unilateralis spore.

Eventually, this single fungal cell finds its way into the ant’s body. Still, the ant notices nothing out of the ordinary. It continues to scavenge and dig. All the while, this fungus feeds on the fluids and soft tissue of the ant. Growing and growing until it eventually accounts for the majority of the ant’s total mass. Then, as the multicellular fungus nears the end of its feeding, something very strange happens.

Fungal stalk growing from the head of an ant.

Fungal stalk growing from the head of an ant.

What’s the Point?

The O. unilateralis cells cluster together and produce a thin, almost needlelike structure that forces deep into the muscle tissue of the ant. While the physical autonomy of the ant is hijacked, the fungus also releases a chemical signal that travels into the brain of the ant. This signal seems to rob the working-class insect of its mental faculties and causes it to leave the nest. On this fungal-chemically induced journey, the ant climbs to the highest point it can access. Nearing the apex of its journey, it clamps its mandible tightly to a leaf or something else it can bite and grip as the needlelike fungal growth tears through the exoskeleton, effectively stapling the ant in place.

Locked tightly in this high position, the ant’s head bursts open and a long stalk grows from the tattered flesh. A new group of spores is released. From a higher vantage point, are carried further and wider by the wind.

There is a bevy of research published on O. unilateralis. One of the most thorough papers on this was published by Charissa de Bekker, et. al. in the journal Integrative and Comparative Biology in 2014.

Horrors All Too Real

A mold, in technical terms, is any species of filamentous fungi. Here is an example of a fungus that can infect a species, feed on it until it overtakes the form, and alter physiology and action. It can control thoughts and function. The idea of a mold that can do the same to a human does not seem that farfetched. The differences between an ant and a human may seem great enough that such a process could be transferable. Many biological functions are already evolutionarily conserved from insects to humans. One example is the core architecture of the circadian clock.

Infected Mia attacking in Resident Evil Biohazard.

Infected Mia attacking in Resident Evil Biohazard.

With this in mind, the horrors of Resident Evil become all the more terrifying. The threat of infection mutating a human into a humanoid shape of mold is suddenly no longer just fiction. It is possible to be eaten away by a fungus that takes away the ability to control movements and thoughts. The molded are more than just in-game enemies and a metaphor for the hive-mind mentality. They are also a distinct threat to what a human could experience as nature grows and evolves. The fact behind the fiction is fascinating, yet brings entirely new scares to this horror franchise.