On November 6, 2017, a developer known as "devops199" accidentally triggered a bug that permanently locked 513,774 ETH across 587 Parity multi-signature wallets. In the now-infamous GitHub issue, they wrote simply: "I accidentally killed it." The private keys to these wallets still worked perfectly, users could prove they owned the funds, but a deleted library contract meant the money was frozen forever. At today's prices, that's about $1.3 billion lost not to hacking or lost keys, but to rigid smart contract architecture. This catastrophic failure highlighted a fundamental problem: blockchain accounts are too inflexible for real-world use.