The late 1990s saw the advent of more malicious malware for the Mac. Discovered a few days before Halloween 1998, the Sevendust virus would remove all files from the infected hard drive, but leave applications and one file named “666” in the Extensions folder. AutoStart, one of the first Mac worms, was also identified that year. The worm that exploited a feature in QuickTime 2.0 was first identified in Tokyo and overwrote data files on infected systems. AutoStart spread to other systems by floppy disk, recordable compact disks, hard disks and disk image files.