Object in Phoenix Lander gets scientists' attention

On Monday, I pointed out a strange feature on the image of Mars’ horizon in the first pictures to get sent back to Earth from the Mars Phoenix Lander. Some dismissed it as an anomaly in the digital photography, but it has appeared on several pictures now. The unusual shape has some researchers very curious:

Here is the picture from Monday:

It’s almost certainly a rock, but Mars doesn’t have many with that luminosity and that shape. Everything else in the view of Phoenix looks dust-covered and relatively small. Its unusual appearance makes it stand out from everything else in the rather bleak landscape.

So what do you think it is? A message from Future Mars? Or a portal to Past Mars? Or just a cool-looking rock that will eventually get used by Hollywood for even less-intelligent fare?

Update: John discovers what the object is, and is thankful that there are snacks on Mars.