In Middle Age, people sincerely believed races of headless people or akephaloi (with their face on their torso, the eyes being either on the chest or on the shoulders) existed in unexplored aeras, like Africa. Notably the Blemmyes, a Nubian tribe that truely existed around the third century of our era who, for some reason historians still don't understand, were always described and drawn as akephaloi, which means we have no realistic testimony to this day.
*EDIT*
OK so singular would be akephalos. Thanks my Greek friend who will recognize himself.

Akephaloi © European beliefs
Drawing © me