I have a function called mc, and I just called it from the command window. Ooops... I typed md("blabla") accidentally.

Guess what, I now have a folder called "blabla".

More testing... trying to return a result from it gives a "file md.prg does not exist". But it works if it's called as a command, on its own. It errors out if I try to create the same folder again.