1670s missing person cases

Fet-Mats or Fat Mats (born Mats Israelsson; died 1677) was a natural mummy found in Sweden in 1719.

The fish-man of Liérganes () is an entity of the mythology of Cantabria, located in the north of Spain. The fish-man would be an amphibian human-looking being, who looked a lot like a metamorphosis of a real human being who was lost at sea. His story was examined by Enlightenment writer Benito Jerónimo Feijoo, who claimed that the story was true.