The "wrong PIX" reversal trick

A stranger sends you a small PIX "by mistake," then contacts you — sometimes pretending to be the bank — asking you to send it back to a different key. The money they sent may itself be stolen, making you part of laundering it; or the "refund" simply sends your own money to them.

What to do: don't move it yourself. If you truly received money in error, report it to your bank and let them handle the return through official channels.