Here’s something I’m 100 percent certain of: you’ve never heard of the Covasna, an inconspicuous tributary of an obscure river located somewhere in Romania. There’s no way you could point out the Covasna on a map — even I have no idea where it is, and I’m writing about it. But though you and I don’t know where or, indeed, what the Covasna is, let’s take a quick look it.

Why?

Because this little stream is the perfect illustration of how hoaxes, memes and fake news go viral.

The Covasna is just five and a half miles long. It flows into the Jijia River, which feeds into the Prut River. Have you heard of either of them? I’m going to guess no. But chances are you’re familiar with the Danube, of waltz king Johann Strauss’ “The Blue Danube” fame, into which the Prut River empties. And where does the Danube wind up? The Black Sea, one of the largest bodies of water in the world, stretching across 168,500 square miles and fed by one-third of the rivers in Europe.

And it all starts with a trickle of water somewhere in Eastern Europe.

Like the Covasna, the spread of viral content originates with small tributaries that merge and converge until they’re omnipresent in the online content and social media we consume. Though some subscribe to a fastigiate tree model of how viral videos and news are spread, with a single source that divides into a self-contained column of linear branches all reaching in the same direction, this model isn’t accurate.

The sources of viral content, and the means by which they spread it, are far messier. But regardless of how it reaches you, this heavily shared media must possess a specific set of qualities or it simply won’t flow along Twitter, Facebook, YouTube, Reddit, or even old school email, the large and small information channels of the 21st century.

The anatomy of viral content

Drop a rock in the Covasna and isn’t going anywhere. But if you’ve got a boat built to withstand the twin scourges of skepticism and cynicism, it just might make it all the way to the Black Sea. This is what it takes to design such a boat.

1. It has to be believable

People aren’t stupid. They really aren’t. If a video or news story looks fake to them, they aren’t going to share it.

With viral content, it’s only amazing if it’s true. A video with obvious CGI, no matter how stunning or shocking, isn’t as impressive as a “real” incident caught on camera. A humorous yarn, colored with exaggeration, polished with pitch-perfect dialog, and capped with the perfect punchline, isn’t as inspiring as a true story told in a casual, off-the-cuff style.

“When you first hear the story, you are completely amazed that such a thing has occurred. When told correctly, [it] will have you on the edge of your seat. It’s human nature to want to spread this feeling to others, and be the one who’s got everyone waiting to hear how the story turns out,” writer Tom Harris explains.

If there seems to be a grain of truth to it — if it seems like it just might be true — and if it appears to come from a reliable source, fits into a common worldview, and has the critical Occam’s razor factor (the simplest answer is usually correct), then it’s on its way to going viral.

2. It has to make you feel something

Intellectual stimulation isn’t enough. It has to meddle with your emotions. Inspiring fear, anger, humor, social or political anxiety, delight or indignation are some of the best routes to virality.

Recently, researchers from the Massachusetts Institute of Technology took a look at the way fake news and misinformation spreads on Twitter. “In a study of 5,000 users, they looked at a random sample of tweets each user may have seen in the 60 days prior to retweeting a rumor,” explains Dom Galeon at Futurism. “The emotional response a tweet generated … played a role in user engagement. Fake news generated replies showing fear, disgust, and surprise.”

A cautionary tale or the condemnation of a particular type of person is particularly easy to spread.

3. It has to include unexpected narrative elements

Images and stories that are shocking, sexy, grotesque or funny are all well and good. But to capture the imagination of the public, there has to be an element of the unexpected. A surprise ending to the video, a plot twist at the end of the story.

The unexpected is what changes a dull anecdote into a great story. It’s the difference between watching a video of a dog chasing some deer through a field, and a video of a dog chasing some deer through a field while in turn being pursued by an irate Brit desperately shouting “Fenton!” at the top of his lungs and calling upon the name of his lord and savior.

“Stories, after all, are much more than vehicles to convey information, they must hold our attention and find their way into our hearts if they are to be memorable,” writes Greg Satell at Forbes, “We don’t need to tap into mysterious powers of influence to make an idea spread. In reality, what’s essential is a good story.”

4. It has to flow easily along social channels

The exact origin of viral content is usually unknown and often anonymous. But this doesn’t matter; it’s how it gets spread that’s important.

As Scientific American notes, “Friends tend to form clusters. So, for instance, because Alice knows Bob and Clive, the latter likely know each other as well, and likely share similar views on many issues. These clusters help establish what social media aficionados think of as an ‘echo chamber.’ Most of us tend to see some memes several times, increasing the likelihood that we too will share them.”

This is what’s known as a “density of social relationships.”

Viral content needs places to go and people to spread it, in other words.

And in truth, it doesn’t even need people anymore.

Mental Floss writer Kate Horowitz has discovered that bots will suffice. “A successful viral story required two elements: a network already flooded with information, and users’ limited attention spans. The more bot posts in a network, the more users were overwhelmed, and the more likely it was that fake news would spread.”

So what it really comes down to are tributaries, like the Covasna. These social channels spread the viral content like water, feeding each other and growing until you’re drowning in a Black Sea of memes and misinformation.

Is there anything to be done?

All we can say at this point is dam(n) your channels.