On 2004-02-02 23:57:38 -0600, (Paul Morris) said:

there is visible a pebble or small stone that has a
very unusual shape: it appears to have two "stalks"
that protrude upwards (rather like the stalks
or antennae of a snail).

I noticed that too, yesterday. It is visible more clearly in the
full-resolution TIFF image available from this page:

http://photojournal.jpl.nasa.gov/catalog/PIA05199

I don't see how that could be a rock, it really doesn't look like one at
all. I expect it's either some piece of debris that came off the
spacecraft, or else it could be what it looks like: a little critter
wandering across the sand, waving its antennae at us.

Somebody should ask JPL for an opinion of whether they can identify it as
anything they sent on the spacecraft. Taking another picture to see if it
has moved might be a good idea too.

Tony Belding, Hamilton Texas