Once, several years ago, I was watching video from LASCO and saw a whole star moving out of phase with the background star field. It never came through the solar system or we would not be here. It was close enough to see go behind the sun on LASCO, moving at astonishing speed. I don't know how I would go about determining it's origin, but it definitely wasn't behaving as though it was part of the relative 'order' of this galaxy.
This cigar shaped asteroid reminds me of the beginning of a sci-fi novel called 'Marrow' by Robert Reed.