A USB Dead Drop is a secret way to anonymously exchange data or information between two people. It is usually done by one person putting data onto a USB drive and then hiding it somewhere in a public place, like a park bench or a parking lot. The other person then looks for the hidden USB drive, plugs it into their computer, and can access the data that was left for them. This way, no one knows who left the USB drive or who received it, so it's a very secure way to share information.