Creeper was an experimental self-replicating program written by Bob Thomas at BBN in 1971. It was designed not to damage but to demonstrate a mobile application. It is generally accepted to be the first computer virus.Creeper infected DECPDP-10 computers running the TENEX operating system.The Reaper program was created to delete the Creeper program.
^IEEE Annals of the History of Computing, Volumes 27-28. IEEE Computer Society, 2005. 74. Retrieved from Google Books on 13 May 2011. "[...]from one machine to another led to experimentation with the Creeper program, which became the world's first computer worm: a computation that used the network to recreate itself on another node, and spread from node to node."