Sun: 4137237 patchadd 106300-01 results in rm -rf / as root (That’s bad)
Microsoft: Computer Hangs While Booting with HP 6L Printer out of Paper (paper-powered pc’s ??? FEED ME!!!)
And I can’t find it now, but back around 12 years ago or so, uninstalling Norton Antivirus resulted in deleting all files not in use. That amuses me.