MacBook creates unnecessary duplicates on micro sd

Whenever I drag and drop a file(let's say Bible Adventures.nes) it tends to create another copy of it named "._Bible Adventures.nes". I tried the "Show Hidden Files" trick by using the Automator to only reveal two hidden files: "Spotlight V100" and "Trash".I don't know why my laptop keeps on doing it, but it stops me from drag and dropping files to my iPlayer .Any ideas?

Backup the important files and format your MicroSD.