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Around 1980/81, a car-pool buddy told me of a story that he had read about a computer virus that constantly evolving. I vaguely remember that it's human programmer had created several early variants that weren't self-sustaining but as they 'died' he would add new characteristics - self-replicating, mirror real code to escape detection, and eventually self-modifying so it could learn and adapt on its own. I don't remember the title or author (or friend, for that matter) but it was the earliest I had heard of a computer virus that evolved. Any thoughts?