Bale
Minion
txt is part of the file name. Windows has a habit of hiding the extension if it is a known file type. Rather than tell you how to make the invisible .txt appear so that you can change it, here's a simpler answer: Try saving the file again, but make sure you save it with .ash at the end. If you do that it won't append .txt invisibly.
Then you can delete slime.txt
Then you can delete slime.txt