Innately, humans are a curious, highly intellectual species. We have an ability that stretches beyond all other species — a unique voice inside of each and every one of our noggins. We can think for ourselves, make assumptions and feel emotions. The power is intoxicating, yet we continue to show a constant desire to obtain more knowledge. That very urge spans back to the creation of humanity when Adam and Eve were cast out of the Garden of Eden by God after they disobeyed his direct order to not eat from the Tree of Knowledge.
Imagine humanity in the form of a little boy poking a dead deer with a stick he found on the side of the road. As children, we learn to juggle new information from our external stimuli — the meaning of life and death, the end of all existence — until adulthood, a stage where we can successfully balance these complex topics. Sometimes our curiosity doesn't always lead to knowledge. Sometimes it leads to death.
In October of 1347, 12 Genoese trading ships docked at the Sicilian port of Messina after a long journey through the Black Sea. People who rushed to greet the men were met with a shocking discovery. Almost all of them were dead. The men "lucky" enough to survive the journey were gravely ill, showing symptoms of an increasingly-high body temperature, an inability to keep down food and mysterious black boils on their extremities and groin areas that oozed pus and blood. Thus, the "Black Death" was born.
Sweeping the world until the early 1350s, the bubonic plague massacred nearly one-third the population of Europe and around 75 million people in total. Our urge to study the disease while the plague was in full force led to even more deaths worldwide. Some tried lancing the buboes and bloodletting, while others flagged themselves with metal-spiked ropes for days in an attempt to plea for forgiveness from God.
The year is 2017, it's been nearly 700 years since the outbreak of the plague. We now have scientists and doctors researching vaccinations and future countermeasures for diseases and epidemics, but would we be ready for a Flood invasion?
A Global Epidemic
Over the past 700 years, human beings have advanced exponentially, both physically and intellectually. Smallpox, the flu, polio and HIV Aids are some of the most impactful diseases in human history, resulting in a rapid increase of global death rates. We've been hit hard several times throughout our history on Earth, but each time after the last, new remedies or even cures release to the public to combat and exterminate the epidemic. As we grow smarter, the global lifespan increases. That is until the Flood take refuge on our home.
Think of the Flood as the Black Death with instincts. The Flood, or Inferi redivivus in Latin, translates to "the dead reincarnated." Having the ability to reanimate a deceased host and survive in -75/+53 degree Celsius temperatures above or in water, the Flood are, according to the Halo wiki Fandom page, "an extremely adaptable, dangerous, and expendable parasitic life form," that were discovered in our galaxy 10,000 years before the events of the Forerunner-Flood war, most likely around the time of the Forerunner-Precursor war. Similar to our Gods, the Halo universe was created by omniscient beings known as the Precursors. Their greatest creation was the Forerunners. The Forerunner-Precursor war meant an end to the Precursor timeline, and those that perished became dust which could regenerate into their past forms. After years and years of remaining in dust form, according to Halo Fandom, this dust:
"...became so corrupted that it could only cause horrific disease and mutation. The Precursors, driven insane by the rebellion of their creations, embraced this corruption and became part of it, becoming the Flood to destroy the Forerunners as a final act of vengeance against them."
Instead of explaining their history in the Halo video game franchise, I want to explore their behavior and biology in order to hypothesize what kind of an effect an outbreak could have on Earth.
The Flood, as you all have probably guessed by now, are an extragalactic, parasitic species that are incredibly adaptive with an accelerated evolution process:
"...where the body of biomatter accelerates its own evolution to the point of a massive biological breakdown, whereby the infection can first take place. The species can reproduce without host bodies, though this is described as a last-ditch effort, and only performed by pure Flood forms."
The trusted method for Flood reproduction is through assimilation of the host. Through "lysogenic reproduction," the viral cells of the Flood splice with the host's cells, injecting a sliver of their own genetic code. The Flood, based off of loose knowledge, can infect any form of life, but are naturally attracted to hosts with a larger brain capacity, claims a user on Halo Waypoint:
"...the Flood can infest any living organism, but that they prefer hosts with a large brain capacity to accelerate the formation and expansion of the Gravemind hive intelligence and the Flood intelligence as a whole. They are only as intelligent as the beings they infect; the more cunning the enemy, the more dangerous the Flood will be."
Though they are as smart as their hosts, the Flood have poor coordination, a weakness that the Covenant and the UNSC have exploited in the Halo franchise.
This Kind Of Evolution Would Confuse Even Darwin
The Flood, similar to all kinds of species on Earth, go through different developmental stages in their course of life: Feral, Coordinated, Interstellar, and Intergalactic. The feral stage is pretty self-explanatory in that they go rampant by communicating through pheromones, whereas the Gravemind controls the Flood in the Coordinated stage. The Interstellar stage consists of total technological control, and once the Flood learns to utilize that technology to travel to uninfected galaxies, they enter the Intergalactic stage.
Among these developmental stages, the Flood takes several different forms, which ultimately guides their attack patterns in combat. The infected forms seen in the picture above are comparable to an r-selected species, which consists of a high volume of offspring with low probability of survival. Think squirrels, just less cute and harmless. As simple as roadkill, the infected forms are quite easy to put down in fewer numbers. The Infected forms as well as the combat forms (which are essentially the hosts deceased body resurrected from the dead) and the carrier fall into the feral form of development. From there on, the Flood types become genetically more complex and physically superior.
We're Gonna Need More Guns
If the Flood were to make their way to Earth, we would need to be extremely prepared. An attack on an unaware public would spell total annihilation. Based off of most #scifi movies, one would think that an alien invasion usually consists of nonlinear chaos, but the Flood's attack pattern is much more efficient. Their attack phase in combat relies on numerical superiority -- the more of them there are, the more likely we get overrun. A rather advanced strategy that the Flood utilizes goes something like this:
"...the Flood uses all of its different forms to kill any enemy it sees. Infection forms swarm across the battlefield in waves, reanimating any corpses they can find, while Combat forms attack and kill any hosts in sight. Pure forms, if present, provide support to Combat forms in a number of ways..."
This idea of close-ranged combat is the key to their success, and with a rapidly growing population big enough to swallow galaxies, success is simple. Once the infected form has taken control of the host's body, they are able to fire the weapons that the dead had previously used. This adaptability completely destroys the need for their own weaponry.
Would We Be Prepared?
Probably not. Even if we evacuated all of the major cities, there would still be a massive amount of people at risk. Considering the billions of people that currently live on Earth, the Flood would quickly infect those vulnerable and continue to spread. We may have the weapon power to slightly halt their expansion, but the odds of an extermination are slim to none. Realistically, an epidemic like the Flood would never actually exist, but what if another plague with similar characteristics and behavioral patterns is on its way? Our natural human curiosity continues to grow stronger as long as our technology continues to advance. My point? If something as volatile and unstoppable as the Flood actually exists, maybe we're better off leaving the unknown a permanent secret.
Take this year's Alien: Covenant as an example. A civilization of colonists are on their way to locate a hospitable planet far off from a presumably dying Earth. Covenant, the ship holding all of the colonists, has traveled a great distance in search of a suitable, alternate planet to Earth. Towards the beginning of the movie, the captain makes a rather one-sided decision to change course when the Covenant transmits an audio signal from what appears to be another human being on a closer planet. This new planet has similar levels of oxygen to Earth, as well as a sufficient water supply, but lacks diversity in flora and fauna. It is through our "observant" nature that we unleash an airborne parasite that, once it comes into contact with a suitable host, "impregnates" them with a creature designed to kill. One thing leads to another and the alien bursts from the back of the human hosts and manages to slip its way onto the Covenant, endangering all of humanity. Go us!
The point is, some things are better off left alone.