Cryptocurrency platform Poly Network, which allows users to swap different types of digital tokens, was the victim of a cryptoheist that resulted in the thief (allegedly just one hacker) to swipe over $600 million of currency. The incident has been dubbed the largest theft of cryptocurrency to date.

The story reads like the beginning of a novel. After the heist, Poly Network posted a letter on Twitter asking the thief to get in touch with them “to work out a solution.” The thief then posted messages that he would return the funds because he was “not very interested in money.” The next day, Poly Network claimed it had received half of the stolen amount back from the thief, in the form of Ether tokens, Polygon tokens and Binance Coin.

The hacker then posted a three-page Q&A self-interview discussing why he did it. According to reports, the hacker said the heist was meant to showcase the vulnerabilities in the Poly Network software and that users should learn from the hack. The hacker wanted to expose the bug, but not cause a “panic in the crypto-world” which is why the hacker took the important coins but left the Dogecoin. According to the thief, “The pain suffered is temporary, but memorable.”

Cryptocurrency continues to be unregulated, so the bigger story is what would have happened if the cryptocurrency hadn’t been returned.