What type of virus was the Michelangelo virus?

The Michelangelo virus was a boot-sector computer virus that was spread through infected floppy disks. The virus copied itself if an infected floppy disk was left overnight inside a computer. At restart, the computer then booted up the floppy disk and copied the virus to the hard drive.

Once a computer became infected by this virus, every floppy disk that was write enabled became infected with the same virus. The virus code, while initially benign, was discovered to have a destructive payload that had the potential to wipe out data inside the hard drive once the computer's internal clock reached March 6.