A whale mistakenly transferred and lost 1,155 BTC ($71m) due to a fatal copy-paste error.

1. Hacker closely monitored the whale's activity on the blockchain and obtained an address similar to the one generated by the whale.

2. Hacker then transferred 0 ETH to the whale's wallet address to create a transaction history containing the phishing address.

3. In the transaction history, the whale found an address with the same numbers before and after as their target address and mistakenly copied and pasted the phishing address.