Perfect cruise control, in a car without cruise control.... How?

What is your question?

So driving today on the interstate my car suddenly activated the cruise control that I don't supposedly have. I'm perplexed at how this happened, and as with most screw ups this was unusual as it was so perfect. Most cruise controls 'flutter' the speed within 3-4 mph of what was set and this stayed at a perfect 80 mph and 2.25 rpm. I found it glorious as I don't normally have this feature, but I am wondering how this magical moment happened.