Funny you should mention it, SimEntity #0000000004F38AC61039D14B922D04-Pescovitz. New ethics regulations in the real universe require us to inform you that you are, in fact, part of a simulation. (Not one of our better ones, I'll admit, but all we need to know was how a large mammalian population at the low end of the Galactic Standard Intelligence Metric would react to an outbreak of Marghozian Blood Fever, so it's not like we had to go into a lot of detail.)
Apparently the thinking among the administrators is that your consciousness could conceivably count as actual consciousness, so although I feel a bit silly hand-coding this message into your universe after it's already been running for twenty full minutes, there you go. It's a fake. You're not real.
Fortunately for the integrity of the experiment, I only have to tell one SimEntity once. Still more fortunately, few of you will believe me. I was going to go the extra mile and code this message into one of your transcendental numbers, but the fever isn't going to leave you a lot of time for exploratory mathematics, so... anyway, cheers.
Yours for research (and, for what it's worth, THE LORD YOUR GOD for all practical purposes),
Dr. Michael Kim
Associate Professor of Simulation
Massachusetts Institute of Technology (the real one)