The closest thing to an answer that I could quickly find was a
remark in space.com saying it was from a site where the rover "Sprit spent the closing months of 2007" ( sic ) so I consulted the
Mars Rover Spirit: Traverse Map Archive and found that this was sometime just before sol ( Martian day ) 1406 of the mission. Then I worked backward from this date in the
Spirit Raw Image archive for the panorama camera, and found that the
image ( included below - "figure" is bottom left ) was taken on sol 1367. There of several of these taken through color filters to make the color images. Note you can see the bottom edge of this raw image in the posted color panorama image, as indicated by a slight change of tone. The portion below it is from sol 1368, and
these are really much more interesting.
I think it's pretty easy to see that the "figure" is just the fractured face of a sculpted rock, the top of which blends into the background. It does not resemble a statuette, as it might appear to.