The Open-Source Fruit Fly Brain Is Now Running Inside Minecraft

Google and the HHMI Janelia Research Campus published the first complete wiring map of a male fruit fly's brain and nervous system on September 3, 2026, and within days developers had wired the data into video games. One project now drives a living fly mob inside Minecraft using nothing but the fly's actual neurons.

What the Fruit Fly Brain Connectome Actually Is

The new dataset, published in the journal Cell, maps 166,700 neurons and roughly 125 million synaptic connections across the fly's brain, both optic lobes, and its ventral nerve cord, the insect equivalent of a spinal cord. Google describes it as the largest brain map by neuron count released to date, about four times the size of the 2020 hemibrain map that covered only 25,000 neurons. It also completes a matching pair with FlyWire, an earlier open-source map of a female fly's brain, letting researchers compare male and female wiring for the first time.

The dataset is free to browse through Neuroglancer, a visualization tool built for exactly this kind of 3D neuron data, and the raw connectivity tables are downloadable for anyone who wants to build with them.

How a Fly's Brain Ended Up Piloting a Minecraft Mob

Developer Evan Sinclair Smith, known online as evnsnclr, posted on September 5 that they had loaded the full 166,700-neuron connectome into a Minecraft project people now nickname "the amazing digital fly." Game events like nearby food, light levels, and other mobs get translated into signals the simulated neurons can read, and the network's output steers a fly character's movement in real time. Nobody is claiming the fly is conscious inside the game. The connectome only supplies the wiring; a developer still decides how sensory data goes in and how neural firing turns into a jump, a turn, or a dash away from danger.

A separate, earlier project takes the idea further. fruitfly-brain-mod, a Fabric mod for Minecraft Java by developer AshtonLong, spawns small red-eyed flies that seek out fermented fruit, feed, reproduce, and flee threats, all driven by a spiking neural simulation running on the FlyWire connectome (138,639 neurons, 15 million connections). Players can open a live overlay and watch the simulated brain fire in real time while the flies go about their business.

The GitHub Repos Behind the Trend

Nearly every piece of this trend lives in the open on GitHub, which is a big part of why it spread so fast.

• Raw connectome data: the MaleCNS dataset is accessible through HHMI Janelia's own tools, with community loaders published for anyone to reuse.
• fruitfly-brain-mod: the Minecraft Fabric mod, released under the MIT license with the bundled connectome data under CC BY-NC 4.0.
• awesome-fly: a curated list tracking connectome projects spun up in the weeks since launch, from game mods to research tools.

Why It Also Became a Meme

The connectome's move into games turned into a genuine internet moment. One engineer wired the same 166,700-neuron brain to a Bitcoin candlestick chart and let it place real trades on Coinbase with a $100 stake, a project now known as Stonkfly. No profitable trading has been demonstrated, but the repository is public and runs on nothing more exotic than Python and a C++ compiler. Other developers have pointed the exact same brain at Doom, Super Mario 64, and Beat Saber, live-streaming the results as the simulated fly stumbles, flies, and occasionally succeeds at tasks its biological ancestors never evolved to handle.

Can You Run a Fruit Fly's Brain in Your Own World?

Yes, at least with fruitfly-brain-mod. It installs like any other Fabric mod: install Fabric Loader, drop the mod jar into your mods folder, and launch. No account, subscription, or extra hardware is required beyond what Minecraft itself needs.

A second, separately built project called FruitFly Brain takes the same idea to Modrinth. It simulates neurons from a different scanned connectome (BANC v888) live in-game and is also a Fabric mod for Minecraft Java 1.20.x. It's listed in minecraft.how's own mods directory once its review finishes. The crypto-trading and other-game demos are separate, standalone projects and do not run inside Minecraft at all.

Sources: Google Research, AshtonLong/fruitfly-brain-mod, Tom's Hardware.