Lots of video games let you take on the role of the anti-hero: Grand Theft Auto, Hitman, even Mario's mischievous alter-ego, Wario.
But there's never been a video game anti-hero quite like Plague Inc. – in this massively successful pandemic simulator, you actually play the role of a deadly and contagious pathogen, hell-bent on wiping humanity off the face of the planet.
Now, in response to public demand via an ongoing petition at Change.org, this wildly popular plague game is going to incorporate a new menace in its chilling disease-spreading simulations: anti-vaxxers.
Anti-vaxxers might sound like a strange inclusion for a video game, but it makes a lot of sense for Plague Inc.
In other games, you might choose to be a warrior, a wizard, or a cleric. In Plague Inc., your options include things like being a virus, a fungus, or perhaps nasty bacteria.
If those character selections sound a little dull, how about conquering the world as a parasite, or the Black Death? Or maybe you'd like to try your chances as a deadly lab-engineered bio-weapon?
It's this limitless amount of pathogenic possibilities that has seen Plague Inc. notch up some 120 million players across the world since it was released, with the developers jokingly claiming the game has 'infected' 1.6 percent of the world's population.
If it all sounds in poor taste, consider this: the game's creator, UK-based economics graduate James Vaughan, used his knowledge of economic modelling to build a game that could realistically explore the ways diseases spread between various countries, affected by a host of factors such as transmissibility, lethality, mutations, and weather conditions.
It might be entertainment, but it's also an approachable introduction to the way disease epidemics can actually play out.
Vaughan has even given a talk about infectious disease modelling at the Centres for Disease Control and Prevention (CDC), while a more recent Plague Inc. follow-up title has been suggested to contain a few pointers for the Pentagon.
"It was more about building a game I wanted to play," Vaughan previously told Apple in an App Store developer feature.
"The fact that Plague Inc. is fun and based on scientific principle means education is in its DNA."
This is where the new anti-vaxxers game scenario comes in.
Part of the reason for the game's ongoing success has been an almost endless stream of new content since the title was first launched in 2012.
Many of these updates have a fantastic bent: zombie plagues, vampiric infections, and a 'Simian Flu' inspired by the Planet of the Apes saga.
But not all the new additions are fictional; some act as topical reflections of the global health landscape we see around us every day.
One recent update was centred around a Science Denial scenario: as the world is menaced by a virulent pathogen, scientists seek refuge in a world ruled by an anti-science mob of flat-Earthers and climate change deniers, who break into labs and destroy research, unwittingly aiding the disease's spread.
In a similar spirit, Ndemic Creations, the company behind the game, has now announced they'll also be incorporating anti-vaxxers into the Plague Inc. mix, citing the popularity of a Change.org petition demanding the feature (with over 20,000 backers at time of writing).
It's not yet known what exact form the anti-vaxxers update will take, but much like they do in real life, the in-game anti-vaxxers might perhaps perpetuate ill-informed conspiracies online, enabling anti-vax hotspots to emerge inside countries, and ultimately encouraging the spread of terrible, fatal diseases.
It would be nice if these awful real-world outbreaks were hermetically sealed inside the harmless, fictional universe of a game world.
Sadly, they're not.
One thing we can hope, though, is that the new Plague Inc. update helps educate people about the harmfulness of the anti-vaxxer community, by demonstrating the chilling ways their actions help distribute disease across the globe.
Games are one thing. But in the real world, nobody should be rooting for the pathogen.