Few games spotlight player’s animal instincts. Most MMO worlds more or less resemble our own, whether they be set in a fantasy or science fiction universe; there are laws that must be obeyed and cooperation is needed to succeed. Even survival games like Rust and DayZ emphasize working together for security. What about a game where everyone is in it for themselves, where there’s no social contract, where self-interest is the only axiom? I finally found the world that excels at selfish PvP: Slither.io.

You begin life as a colorful worm on a grey honeycomb surface. The 2D world is cluttered with glowing orbs to be eaten: the more you eat, the bigger you become; the more food available, the stronger your appearance. It’s not a feast but a competition. An endless supply of tube-shaped players slide across the jungle, a species that specializes in killing its own kind. If your googley-eyed face touches another worm you pop into bunches of scintillating globes. Delicious.

There’s no limit to your size and the rule seems to be bigger is better. It’s misleading. Cows are enormous compared to the fly but their size attracts parasites, and the cow can’t avoid the fly no matter how much they might shake their head and swing their tail. So too do bigger worms attract flies, except unlike the cow smaller worms kill. Bigger worms lose the finesse of agile movements, making them vulnerable to bite-sized enemies. One brash miniature can pop a goliath, a pin attacking a balloon, and fill himself up on globules before being destroyed by another.

Slither is the state of nature where every worm is out for themselves; it’s what lurks beneath primal pond scum, the law of the wild, where the need to survive and grow is the only edict. Every player does what it takes to become alpha. But to have your name on the leaderboard is a temporary victory, just like the Dinosaur’s rule over the Earth was an ephemeral 65 million years. It's a game of who can survive the longest. Whether players recognize it or not, they automatically adopt strategies to outlive their kin.

Manipulators use psychological warfare to create anxiety in their victims, waiting for another worm to slip up so they can absorb the remains of a nervous player. Riding next to a worm, they boost when they boost, turn when they turn, follow their movements and slide close but never so close to their target’s ribs that they jeopardize their own existence. They’re vultures shouting insults as they circle above.

Whereas attack-worms rely on speed boosting, using some of their stored orbs to sprint and cut-off the unsuspecting. Or they coil around worms and wait patiently for a mistake—the boa constrictor of Slither.io.

Like any species there are also players who break the rules. Cheaters install a plugin to zoom in and out freely, replacing their eyes with binoculars. They no longer have to be overly cautious but can plan their attacks in advance. Cheaters do pay a price. Zooming out too far makes them susceptible to tiny new spawns who can easily swoop in and burst the cheater’s superiority.

No matter the strategy a player emulates they are eventually killed by greed—the sin that looms amid the orbs. Fiends descending on colorful orbs collide with each other, a mosh pit no one escapes from. They boost for a meal and get a nibble before respawning. Greed is as reliable as the tides: it retreats for a moment before crashing the worm.

Once you understand player’s natural greed it’s easy to survive. Watch a large worm explode and madness descends on its carrion. Wait for the beasts to pop each other before swallowing them whole. If I’m big enough I won’t gorge or try to scare worms away. I’ll encircle the blowout and gobble them together. “Thank you for picking up those orbs for me. I’ll take those now.”

Only the worm who controls their greed survives. Playing aggressive works when it's combined with caution: prudence. I accelerate only when I have room, when I know there’s no surreptitious worm trying to block me in against another body or fly in front of me during a dangerous turn. Keep your instincts in check or end up extinct.

There are plenty of orbs to go around but nobody seems to pay attention to abundance. Even in the garden you want more. Mahatma Gandhi is credited with saying, “Earth provides enough to satisfy every man's needs, but not every man's greed.” It’s true. My worm is never big enough.

The outward appearance of simplicity often belies a game's depth. Slither.io is a clear derivative of Snake but it relies on the psychology of players for spontaneous interactions that are both basic and profound. A person is navigating with a mouse in hand, only interested in helping themselves. They can wait and watch or use their bodies to eliminate yours, motivated by the desire for more. While others use base impulses against the greedy. It's a microcosm of self-interested interactions.

I’m not suggesting Slither.io was created as a commentary. Slither.io is first a game, a magic circle where self-preservation is the only rule, and it works well. Player actions are the emergent property, the happy consequence of a great rule-set. Applying pressure to worms, encircling them, running them into a corner, and growing bigger is endlessly entertaining. I happily indulge in greed when playing: never satisfied, always hungry for more. In the worm jungle I am the devourer of worlds, the worm that transforms life into light. I'll never be satisfied until I'm the last worm slithering.