Not quite the same, but one time a guy I worked with decided to "clean up" things on a NCR Unix system and set the ownership of various system files to whatever

Not quite the same, but one time a guy I worked with decided to "clean up" things on a NCR Unix system and set the ownership of various system files to whatever he thought made the most sense. This broke all the stuff that relied on setuid to function correctly. He then went to lunch while the machine slowly ground to a halt. I had to boot from tape and figure out how to fix things from there.