Ghost Pirates

There is a widespread belief among the more experienced space crews that there is a tribe of space pirates that live in interstellar space and prey on humanity's ships.
Stories include tales of cannibalism, powers of invisibility and the ability to breath vacuum.
They are also known variously as 'corsairs', 'predators' and even 'flying dutchmen' (for reasons that are not all that clear).

Of course, none of this has ever been substantiated - and it remains a colourful myth - much called upon by the more lurid tri-v film-makers