In the beginning, the blockchain was about money. Bitcoin, which first appeared in early 2009, appealed to the anarcho-capitalist longing for a way to have currencies and markets untethered from clumsy, quasi-democratic governments. To care about Bitcoin one had to be at least a little obsessed with the means of transaction.

Gradually that started to change. People began realizing that the more or less same blockchain tech could do other things. Some people spun up a decentralized Domain Name System (Namecoin) and a decentralized Twitter (Twister). The apotheosis of that recognition came with a late 2013 whitepaper about something called Ethereum, proposed by the 19-year-old Vitalik Buterin. He had been roving among Mediterranean cypherpunk hackerspaces and writing in Bitcoin Magazine. He realized what was possible.

The public unveiling of Ethereum happened on January 26, 2014, at a Bitcoin conference in Miami. Buterin proceeded through a litany: not just blockchains of money but blockchains of whatever you can program, a universal computer with no one in charge. There would be crop insurance and peer-to-peer gambling; self-executing financial instruments and a decentralized Dropbox. There would be entire decentralized autonomous organizations, a new kind of lawless firm that lives in jointly executed code.

Then came the mic drop, as he stepped away from the podium: “And perhaps maybe even Skynet.”

Skynet, you may recall, is the renegade military robot network in the Terminator movies that decides to exterminate the human race. At least a few audience members laughed at what may or may not have been a joke.

Whatever it was, it was serious, because Ethereum really does enable self-executing, irrevocable batches of code that turn on their creators. A kind of Skynet already exists. Bitcoin and Ethereum both use proof-of-work algorithms that burn through electricity to keep their networks secure. This means the network’s users have a vested interest in helping to make their planet uninhabitable; if the burning stopped, their digital riches would shed value. This is just one of the many ways that the quest for magic crypto-tokens might incentivize us into a real-world dark alley.

Buterin is now working to steer Ethereum away from the proof-of-work dead end. It remains to be seen how well his charismatic authority can steer a network with no central command and control. There is no censorship button. He can’t just devise, he has to persuade. Buterin may be a “benevolent dictator for life” in the mold of past open-source hacker-founders, but to whatever extent Ethereum delivers a Skynet, there may be little he can do to stop it.