Dancing Plague of 1518
So I remember looking into this a while ago, and I don't really have proof, but it seems like the description of "dance" is probably misleading. There's, for instance, something called St. Vitis' Dance, which is a neurological condition people still get today. You can look at videos of that and I don't think any modern person would possibly describe that as dancing, but that's how it was perceived in an older age. As fascinating as the case of the dancing plague is, I suspect it was a disease with the more mundane symptom of muscular dyskinesia or dystonia and we're imagining something akin to actual dancing.Again, I have no proof. It just seems like we're taking the descriptions we have too literally from an era where medical terminology was often metaphorical and made by people with an extremely limited understanding of disease.