Dangerous programs

I once released a spamming tool on /b/ that zeroed out the user's hard disk except for the boot sector, into which was installed some code which displayed a duckroll upon starting the computer, and hanging.

Tell me your dangerous programs you've written, /prog/.

Did it spam "Nyoro~n" or something? Also that is not dangerous. You know nothing about dangerous. Even a basic network worm is more dangerous since it causes your ISP to shut down your internet connection and you will actually have to communicate socially to get it back up.

Come back when you have coded a cruel angel to wipe out and replace the human race..