In 1969 BBN Technologies’ programmer Bob Thomas created the first virus named Creeper. The virus was a self-replicating worm that infected DEC’s PDP-10 and spreaded itself to computers on the ARPANET (the US Department of Defense’s prototype of the Internet).
Upon the infection the virus displayed to the victims a message "I’m the creeper. catch me if you can!". Creeper worm was just an experiment but various threat actors quickly adopted the thing for their own purposes.