Elk Cloner

A program called Elk Cloner is credited with being the first computer virus to appear "in the wild" - that is, outside the lab where it was created. It was written in 1982 by Rich Skrenta and was originally meant to be a joke. The virus embedded in a game would release on the 50th time of starting the game where it would show a blank screen that read a poem about the virus and then infect the PC.