How to copy or (quickly-and-easily) backup a "special file"?
Solution 1:
The files in /dev/ folder are special, in a way that they represent devices on the machine, and are not regular files that have content in them. That file probably represents a flash drive you plugged in to your computer, or a USB bus. If it's a USB flash drive, mounting it first, then copying it's contents will do the trick. You could also try backing up the whole disk as an image.
https://help.ubuntu.com/community/Mount - how to mount. How to make a disk image and restore from it later? - check the answer about 'dd' and 'gparted' utilities.