The Creeper virus was first detected on ARPANET, the forerunner of the Internet in the early 1970s. Creeper was an experimental self-replicating program written by Bob Thomas at BBN in 1971.Creeper used the ARPANET to infect DEC PDP-10 computers running the TENEX operating system. Creeper gained access via the ARPANET and copied itself to the remote system where the message, "I'm the creeper, catch me if you can!" was displayed. The Reaper program was created to delete Creeper.A program called "Rother J" was the first computer virus to appear "in the wild" — that is, outside the single computer or lab where it was created. This virus was created as a practical joke when Richard Skrenta was still in high school. It was injected in a game on a floppy disk. On its 50th use the Elk Cloner virus would be activated, infecting the computer and displaying a short poem beginning "Elk Cloner: The program with a personality...."
