8 min read

Building Beyond: Invasive Economics

Building Beyond is an ongoing series of conversations about how much fun worldbuilding can be. Building a world doesn’t have to be hard or scary. Let’s give it a try, together.


The ecosystem that is the global economy has fallen victim to an incredibly invasive species.


K. O’Keefe Thomas is a Taos Toolbox alum and writes SFF fiction in Alberta, Canada. She is an economist in her day job and spends a lot of time taking care of cats and dogs. You can find her blog at economous.ca and she is on Twitter (sometimes) at @thomask8D.

Gailey: What's the invasive species look like? What is it called?

K: How it looks depends on its environment.

At stores you can find it in the card reader at checkout—it’s like an encrusting lichen that forms around the slot for the card and spreads over the rest of the machine. It isn’t actually lichen, but it’s kind of green-grey like that and it digs in on the thing it grows on, so you can’t just wipe it off. Generally, as long as the card reader gets swiped regularly it remains functional for a while. It’s denser and tougher on automated teller machines, and that’s why those have largely been taken out of service and gone away. Data centers for banks get particularly crusty—they still function, but the useful life of individual servers is days or weeks now, not years.

The prevailing theory is that what the species lives on is friction or drag, not just of the card swipe but of the transactions too. ATM fees are pure friction, unlike buying gum, or cigarettes or groceries. After you swipe your card, you may find particles of it in your purse or wallet, clinging to your credit or debit card, but you can just dust those off. It’s very unlikely you’ll swipe your card enough for it to be a problem. If you live some place that still has cash, the longer you hold on to it, the more likely it is to get crusty. Exchange of one country’s physical currency for another’s generates a lot of dust and crust. The patina on coins, especially low value coins like pennies, is just wild.

It doesn’t grow on goods for sale, more the infrastructure for trade and transactions. In shipping, it has been particularly aggressive. It builds up on train tracks and highways. Maritime shipping has had it the worst, with buildup on actual vessels, but also, in some cases, waterways. The further things have to travel, the more friction, the more build up. The more times this have to change hands, the thicker and tougher the layer of lichen developed en route.

In early days, folks didn’t know it was all the same species, and didn’t relate what they were scraping off hulls with the stuff flaking off ATM machines. As a result, it had a few different names when researchers thought they were different things. Almost everyone just refers to it as V. marginibus now. I’ve seen people on Twitter call it the marg, or just Marge—this is why I saw a bunch of Marge Simpson t-shirts at Hot Topic when I was taking samples at the mall.

Gailey: How did Marge get into the economy? Why is it hard to eradicate?

K: Scientists haven’t come to an agreement on where it came from. The first theory was that it had some relation to coralline algae from beneath the retreating arctic ice. This was posited, in part because one of the first places V. marginibus was noticed was freighters transiting northern passages that opened up in more recent years. This has largely been discredited, but the theory that has gotten the most traction is that it is not terrestrial. The researchers who have access to samples and data that might support that haven’t published yet because they’ve had to sign NDAs with a private space launch company—and you can bet physical copies of those legal documents are absolutely encrusted.

It’s relatively easy to remove, but it just grows back. The balance of literature published on mitigation and removal indicates that as more effort is invested in removal, V. marginibus grows back more vigorously. Most organizations have adopted approaches that do the minimum.

The one way we’ve seen to inhibit it or eliminate it is to remove the energy it lives on—removal of the relevant transactions. For example, most cities around the world have closed big financial centers and stock exchange buildings because they got so overrun. The V. marginibus encrusting those buildings receded and died when the buildings stopped being used that way. In Frankfurt, when they repurposed their stock exchange building into housing, the only units that experienced any regrowth were the units they were charging rent on.

Gailey: What impact is Marge having? Will the ecosystem survive, or collapse?

K: The impacts have been sector and country specific. There has been a race to catalog and quantify how intent and power dynamics that are relatively invisible influence the process of growth. Shipping things and travelling has become more expensive, but that has resulted in a shift to prioritize locally made things, as much as possible. There is some question as to whether certain canals will remain viable for cargo ships over time.

Worker collectives, nonprofits, and public sector undertakings have generally had more success in minimizing the impact of V. marginibus. Countries that had a lot of public provision of services before Marge were better positioned to navigate the disruption. Countries whose economies were organized around large, for profit companies have experienced a lot of strife, and in some cases, rapid reorganization of their industrial base. Unions have had some protective effect, but cynical attempts to unionize that prioritize slowing the destructive effects of V. marginibus without prioritizing workers rights have been significantly less effective.

Our economy as we knew it before will not survive, even as corporations cling to it. But we will survive as we find other ways of living and organizing ourselves. I visited a hybrid tech manufacturing and farming co-op, and they hardly had any V. marginibus anywhere on site. Likewise, at my university, the servers in my department, even the car I use going around to support research, have very little buildup. We will evolve to co-exist.


Rem Wigmore is a speculative fiction writer based in Aotearoa. Their novel Foxhunt is forthcoming from Queen of Swords Press in 2021, and their other works include Riverwitch and The Wind City, both finalists for the Sir Julius Vogel Award, as well as short fiction in a range of publications. Rem’s probably a changeling, but you’re stuck with them now. The coffee here is just too good. Rem can be found on twitter as @faewriter.

Gailey: What's the invasive species look like? What is it called?

Rem: The most weasel (mustela virtualis) is hard to get a look at due to its speed and small size – yes, despite the name, the most weasel is even smaller than its cousin the least weasel. According to hearsay, the name began as mostly weasel and then, like the weasel itself, mutated rapidly.

Specialised cameras have picked up blurred images, a flash of sparking fur before the creature encrypts itself. But most weasels are best seen in the trail of devastation they leave: burnt-out wires, bitten coins…

Gailey: How did the weasels get into the economy? Why are they hard to eradicate?

Rem: The recession left the global economy vulnerable to cryptomustelids. It isn’t their fault: they’re just acting in their nature, and their nature is greed. Tiny and adaptable enough to enter the economy through the smallest of profit margins, most weasels’ habit of ‘surplus killing’ and hoarding more energy than they can consume makes even a small weasel infestation a big problem. Unfortunately their incorporeal forms and furtive burrows - deep in data mines - make them hard to isolate.

Anyone familiar with pest management of invasive stoats and the like in New Zealand or invasive mongooses in Hawaii will be well aware of the difficulties of catching mustelids. Leaving traps has had only limited success, the most weasel easily learning to navigate past CAPTCHA verifications and password protections.

One more humane pest management strategy is the idea of depriving them of their food source or preferred habitat, leaving no reason for them to stay in the virtual sphere. Socialism has been trialed as a method of most weasel control, and shows some promise in reducing weasel numbers, but larger-scale studies are needed before this can be widely implemented.

Gailey: What's the impact weasels are having? Will the ecosystem survive, or collapse?

Rem: With their diet, eating electricity and producing heat, most weasels are disastrous for the environment. The economy is suffering, stocks plummeting any time there’s so much as a hint of weasel infestation. The most weasel has a devastating impact on an ecosystem that simply didn’t evolve to withstand it.

You may insist it’s not all weasels, but that’s beside the point: it’s most weasels. And it’s a shame, because they’re beautiful creatures, somewhere they aren’t supposed to be. Mustelids were never meant to be part of the economy, and certainly never meant to be digital. Some of their cousins have made it into the economy, but only dead, as pelts and furs. Maybe this is the weasel’s revenge.

Still, there seems hope that with effort and proper legislation, we can make a full recovery – but that depends on having proper, rigorous studies, and you know how little funding there’s been for science since the weasels got in.


My invasive species would take the form of a microscopic parasitoid wasp. The wasp’s larvae kill and consume the concept of money. You know you’ve got an infestation when people start forgetting that money exists. All the customers in a grocery store start walking out with their full carts, calling “thanks! see you next week!” A bank’s employees show up for work and stand behind the counter dispensing advice, and customers who walk in hoping to make a deposit leave with a firmer dedication to reinforcing boundaries with their in-laws. Unfortunately, the wasps are impossible to eradicate, because once they’ve established a presence in an area, it’s really hard to remember why they were ever a problem; you can’t miss something you’ve forgotten ever existed.

All of these possibilities are just beginnings. Rem’s weasels are the start of an incredibly creative and fun linguistic romp. K’s lichenous growth is the entry point for a story about how people might be compelled to build a utopia. My parasitoid wasps are the beginning of a tale of forgetting; if the wasps begin to mutate, what else might they devour?

How would your hypothetical economy fall victim to an invasive species? How would the species be introduced into the ecosystem? What steps would be taken to try to manage the situation?

Do whatever you want with these questions. You can write something down in the comments or on social media or in a notebook nobody will ever see. You can draw or paint or sit down a friend and talk their ear off about your ideas. You can stare at the horizon and imagine, letting the infinite landscape of your mind unfold just a little farther than it did yesterday. No matter what you do, take pride in the knowledge that you’re creating something that has never existed before. You’re building a little corner of a whole new world.

That’s amazing.


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—Gailey