How to unmask hidden files on USB drives on Windows

Suddenly, a few days ago, someone asked me for my flash drive and he was acquaintance of me so I gracefully handed it, furthermore it seemed that he was in a rush so I didn’t carefully thought about it. Half an hour past that event I asked him for the usb because I noticed he wasn’t using it anymore. I took the usb and inserted onto a machine (not my personal one, thankfully) and weirdly all of the files on the drive had the appearance of a shortcut icon.