Elk Cloner

Elk Cloner is one of the first known microcomputer viruses that spread "in the wild", i.e., outside the computer system or laboratory in which it was written. It attached itself to the Apple II operating system and spread by floppy disk. It was written around 1982 by programmer and entrepreneur Rich Skrenta as a 15-year-old high school student, originally as a joke, and put onto a game disk.