Resident Evil: Pwnsome Pathogens
Quick backstory: Resident Evil is one of my favorite series. When I first got my very own Playstation Resident Evil was one of the first games that I rented out for it. It was in 3D, and it was a glorious B-movie experience in videogame form, and it managed to make me jump in my seat a few times. There are many specific things about the series that I love, like the characters, the good use of music to set the mood, the ridiculous dialogue and plot lines (true story, I wrote a short screenplay for a Resident Evil movie in highschool), but the thing about the series I'd like to talk about right now is the awesome viruses and parasites that produce the various creatures that the protaganists fight during the course of the games.
First of all, a little nitpicking from my scientific side: no virus or parasites work the way the critters of Resident Evil work. They just don't. We see mutations that cause instant growth, and metabolism doesn't work that way. I suppose we could assume that in the case of mutations that couse instant growth the individual or creature who grew was actually hording up mass before hand and actually weighed far more then they appeared to, but I assume that the creatures that grow instantly just get that energy from nowhere. Creatures that grow more slowly could be explained by an enhanced metabolism caused by the virus they were infected with that causes the growth over time, but creatures like the G-Type monstrosity that William Birken transformed into apparently grow larger with no apparent source of energy that could explain the increase in mass. A big offender of "Mass and energy from nowhere" in the games is Osmund Saddler, the primary villain of Resident Evil 4, who transforms into a huge monster at the end of the game and while human can apparently hide huge tentacles that can kill a man in his robes. That last part... um, it's not as bad as it sounds, folks, but it still messes with the laws of physics.
Anyways Resident Evil viruses and parasites=Totally impossible. But that's part of what makes them so much fun. I love psuedo-science like this, it's great fun. I love to categorize them and try to figure out their effects. A virus that reanimates the dead and infects animals in such a way to make them monsterously feral and in some cases gigantic? Awesome. A virus that instills great regenerative powers to it's host at the cost of constantly mutating him or her into a monster, a monster that seeks to propagate itself by injecting hapless bystanders with embryos of itself? Sweet. An ancient photo sensative parasite that induces psychotic maddness in it's host and subjegates the hosts will to a communal hive mind ruled by an individual infected with a "Queen" parasite? Good times.
Some history on the origins of the monster making agents in the games. Most of them are the creations of the Umbrella corporation. I could go more indepth in the history of the people behind this evil mega corporation, but that would leave less time to talk about virus goodness. Suffice it to say that there are a lot of people without morals and with high intelligence who think that making horrible monster making viruses is an awesome passtime. These people all work for Umbrella.
(I 'gathered this info around the internet, and I give some of my interpretations on what's going on with the Viruses and parasites)
T-Virus- This little guy is the iconic virus of the series and my personal favorite. The T-Virus (the "T" stands for Tyrant) is not the first mutagenic virus Umbrella got it's hand on, in fact it was developed from a previous Virus that Umbrella had access to, but it is the companies most effective monster maker and it's Bioweapons are mostly T-Virus creations. The T-Viruses primary purpose seems to be making Tyrant's, which are large Frankenstein's Monster type critters that have exposed hearts beating on their chests and claws on their hands. (say, Tyrant-Virus, Tyrant Bioweapons... you don't think that was maybe planned, do you?) Tyrant Bioweapons are generally final bosses in a lot of the games, they are very formidible. The T-Virus has also been used to make other bioweapon's, such as virus infected sharks and dogs known as Neptune and Cerberus respectively. The T-Virus in addition to some degree of genetic manipulation (I suspect that the T-Virus is used as a crutch to help patch up the problems caused by imperfect genetic engineering) is used to create humanoid lizard like monsters that are known as Hunters. These are most of the purposely built bioweapons of Umbrella, the Zombies that the series are famous for are merely the result of accidental release of the T-Virus and are not meant to be bioweapons. The T-Virus causes zombies to be created by taking over a host and killing them, while altering the bodies cells so that they no longer acquire energy by respiration but by the bodies cells effectively cannabilizing themselves. This causes the zombie to rot and appear like movie zombies, as will as making them immune from most hazards that would hinder the living. All organs but the brain are unnecessary in a Zombie, which makes them very resistent to firearm damage that isn't aimed at their heads. Zombies that are "Killed" (receive enough damage to cease functioning but who don't have their heads destroyed) will sometimes have the T-Virus go hyperactive in their bodies and cause some changes that will make them transform into a "crimson head". They'll start to bleed profusely from their heads because they're cells are breaking down to gather energy for their change, and their hands will develope claws. They are much faster and more violent in this state, but they can also be permentently killed because the "crimson head" transformation leaves their regenerative abilities exhausted. Crimson heads can mutate into lickers, skinless zombies with enlongated stabbing tongues with exposed brains who crawl alongs ceilings. The T-Virus can infect a large number of animal species, and it's dangerous because if i is released into an area it can cause an outbreak, which might be the first step in a zombie apocalypse.
G-Virus- The G-Virus is the descendent of the T-Virus... sort of. It's creation is pretty complicated, involving the imprisoned daughter of an architect who was locked away for decades in a research facility and subjected to so many viruses (including the T-Virus) that she became a horrible monster. The G-Virus was discovered in her blood. The G-Virus (the "G" stands for Gene) causes constant mutations with the benefit of regeneration. The G-Virus is actually a bit safer then the T-Virus, to my mode of thinking. The G-Virus produces a single creature of immense power, pretty much a Tyrant that is nearly unkillable by conventional weapons, but that creature can't easily replicate itself. The G-Virus can only be spread by direct injection, while the T-Virus seems to be able to be tranmitted via air and water and direct bodily fluid contact vectors. One monster is better then a legion of zombies, am I right? Still, the creatures created by the G-Virus isn't completely without means of reproducing itself, it can place embryos of itself into people to spread itself. If the person is incompatible the person will eventuall reinact a scene from aliens and the embryo will burst from their chest. Though incomplete the creature will quickly grow to immense size and attack all those who are near. If the person is compatible, like a family member, the embryo will take over the person's cells from the inside and turn them into another G-Type monster.
Las Plagas- Not an Umbrella creation, and in fact not even a virus. Las Plagas (spanish for "the plague" apparently) is an "Invasion of the body snatchers" type parasitic critter that attaches itself to a persons nervous system and takes them over. Las Plagas doesn't seem to cause mutations to a persons genetic structure, rather all the changes it causes seems to be physical in nature. When an individual is taken over by a plaga parasite and their head is destroyed and a tentacle pops out, that tentacle is not a part of the person, but rather it is a part of the plaga that is in their body and using them as a puppet. Plagas are sensitive to light, and during the day they won't pop out of a person body. Nighttime is a different matter, though. Avoid headshots. Plagas in their natural form can infect any creature of a suitable size, which seems to include humans known as Los Ganados (The herd, I believe) or dogs and wolves, but not crows. In addition to these kinds of plagas there are "Queen" plagas that allow the people who are infected with them to control individuals and creatures containing lesser plagas, these Queens can also turn their hosts into highly dangerous bosses. These are not the only Los Plagas derived creatures that are in existence, though. The people who unearthed the plagas experimented with them in order to produce a group of monsters that would rival anything Umbrella ever came up with. First are the El Gigente (The giants), literal giants that contain massive plagas in their backs. It's my belief that the plagas in their backs in some way affect growth hormones and perhaps reinforces the giants bodies to allow them to move. Another giant critter made with the plagas is Del Lago (Of the Lake, I believe). Del Lago is a giant... thing, that is in the lake nearby the village that the Ganados live in. Whatever makes El Gigente so huge is at work with Del Lago too. Novistadors are apparently the result of combining plaga genes with insect genes, they are horrible giant bugs that you must kill with shotguns. Bugs, brrr. There are creatures called Garradors that are blind and who have plagas exposed on their backs, they are blind but they have powerful metal claws surgically grafted to them. Arguably the most terrifying plagas derived creatures are the Regenerators. They look evil, and you can hear them as they come for you. They contain plagas in their bodies that regerate damage until they are destroyed. If you don't find a way to kill the parasites on their bodies they are damn near unkillable. Finally there are the Verdugo, or Executioners. There are two of them, and they serve as guards for one of the games midbosses. They're reminiscint of the xenomorph from Alien, but they aren't as scary.