In 2019, someone forked a chain from ETH and developed a dedicated wallet. After running it for a while, the developer upgraded it, extracted all users' private keys, and temporarily stored them on a server. A week later, another upgrade was rolled out, removing the private key extraction feature. Originally, the plan was to use these private keys a few years later, but things didn’t go as planned. The server got hacked, and all the private keys were stolen by hackers. The hackers didn’t hold back—they consolidated everything right away. Luckily, there was a database of customer assets. With no other choice, they had to relaunch the chain, have customers re-register, and airdrop the original assets back to them.