To our credit, we manage to not giggle like third-graders for most of the episode, as we discuss the strange belief that one's penis has gone missing, become smaller, or been switched out. A peculiar mix of superstition, body dysmorphia, and curse belief, Koro has many traits of a mass sociogenic illness (MSI) and is "contagious" to a degree. When we peel back the layers, it's not such a funny topic after all, and falls into the category of suspicious folklore that results in harm: to victims, to endangered species, and to those suspected of witchcraft.