They really are terrifying. It's hard to say exactly why this is so, but I think it has something to do with how they can occur (some protein randomly misfoldin

They really are terrifying. It's hard to say exactly why this is so, but I think it has something to do with how they can occur (some protein randomly misfolding) and that they aren't really "alive", in the same sense that viruses and bacteria are. You can kinda forgive viruses and bacteria: they're just looking to survive and multiply, just like us. In some cases they monopolise so much of their hosts' resources, or some really critical resource, that the host dies. But Prions, uhhhhh.... They're just kinda these unnatural things that go wrong and then kill you in pretty awful ways. Though not because they necessarily need to out-compete you for resources. Indeed, they don't seem to have any innate preference for existing or not existing, or thriving or not thriving. But they kill you anyway.... Also, just to scare you a little more, one of the more popular (perhaps dominant) theories about Alzheimer-family diseases is that they are initially caused by Prions, that migrate into your brain and start forming amaloid plaques, and then it's all down-hill from there. On the upside, I vaguely remember reading some research on a 'almost ready' drug, initially developed to lessen the negative side-effects of chemo-therapy, that might be effective at stopping the progression of these plaques as they spread throughout the brain. If it actually works, we might have a treatment of AD-family diseases on the market in a year or so (the chemo folks have already gone through the lengthy human safety testing part of the exercise). Not a cure, but at least it might halt or significantly slow progression of symptoms.