This question will scare the living hell out of you?

Actually, this is quite real, and other parasites can indeed have a pronounced impact on the behavior of mammals, including mice and men. There's one that specifically attacks the mouse brain, causing it to lack fear when a cat is present, so that it quickly becomes cat-food, the parasite thereby being ingested by the cat, which then comes out in the feces, which other mice trample over and pick up the same parasite, thus completing the parasite life-cycle. There is still another that's borne by cats (not exactly the same) that has been shown to have an impact on humans that have picked it up, subtly altering the mood and behavior of humans. Let's see if I can find links on those two. It's unfortunately not as rare as one would hope to believe.