Paradoxography
Paradoxography is a genre of Classical literature which deals with the occurrence of abnormal or inexplicable phenomena of the natural or human worlds.
Early surviving examples of the genre include:
It is believed that the pseudo-Aristotelian On Marvellous Things Heard (De mirabilibus auscultationibus) "contains a core of early material from the Hellenistic period which was then added to over time, including some material that was added in the 2nd century C.E. or even later."