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/.

boot sector
The 30-year-old IBM PC architecture is obsolete. Intel is mad because nobody will buy their chips except for "legacy" Windows PC users! Despite what billions spent on marketing and redefining words would have you believe, x86 is a "proprietary legacy system"!