It looks like the latest Mars mystery has been solved. Dashing the hopes of the many people who thought the Curiosity rover had located their lost keys or earrings, NASA has decided that ais actually a piece of plastic.
According to a NASA status report, "The rover team's assessment is that the bright object is something from the rover, not Martian material. It appears to be a shred of plastic material, likely benign, but it has not been definitively identified."
This means some of the mystery is taken out of the equation, but we can still speculate about what that little piece of plastic fell off from and why. Perhaps Curiosity is shedding its winter coat. Maybe the space police are going to come along and write it a ticket for littering.
An image of the object taken by the rover's micro-imager ChemCam shows it looking very different from the Martian surface around it. On closer inspection, I think it looks a bit like a space slug, but that's just wishful thinking on my part.