I was reading an answer on my PC and keeping an eye out for errors in it as I usually do (too much actually). I liked it and upvoted it, and since I found no major errors, I decided to 'cancel' the edit window after I upvoted it.
But accidentally, I hit "save edits" instead of "cancel".
There were no edits made by me. But somehow it saved my "edit" and this is what happened next.
See revision 7. It says "added 6 characters in body".
EDIT — Tried to reproduce it on another answer, but it wasn't funny anymore.