Barnacle Bill
A rock near the Pathfinder landing site on Mars, named and studied by the Sojourner rover using its Alpha Proton X-Ray Spectrometer. It was the first rock on another planet to be analyzed by a rover.
Source: mars.nasa.gov
APODs including "Barnacle Bill"
A Presidential Panorama of Mars
22/07/1997
Scroll right to unfold the latest panorama of the surface of Mars. For best viewing, click and hold on the right arrow icon at the bottom of your browser window. This image, released yesterday and dubbed a "presidential panorama" by the Mars Pathfinder team, shows in colorful detail the surroundings of the Sagan Memorial Station. Now look closely at the big rock midway through the scrolling picture. That rock is called Yogi and just to its left is the robot Sojourner Rover taking measurements of it. Other now-famous rocks are also visible including Barnacle Bill and Flat Top. After this picture was taken Sojourner went on to analyze a rock named Scooby Doo. Intermittent communications problems continue to cause occasional delays in downloading data and images from Mars Pathfinder.