I’ve just found my source code archive dated about twenty years ago. There was a simple DOS COM-files non-destructive infector, sized 287 bytes itself when compiled.
There was a try to write a prepender and show my teacher: “I know assembler kung-fu” (some int 21h function calls, to be honest, though with a feel of proud for careful dealing with memory).
Such executables are in fact not executable nowadays in modern Windows/cmd environment, nevertheless that causes (I suppose) quite an amusing result on virustotal: there are only ten…
…at least as of 2021-03-13.
This file certainly has never been in the wild, I have never neither run it outside my sandbox, nor checked with antivirus software, nor published it.
Keeping sure, modern defenders will not pass such simple undisguised malware, even without a signature in their database.
Joke mode ON Except, maybe, a case when a virus is too simple and undisguised to be detected by too smart and proactive tool.