The infamous Martian Crab Claw!

Panoramic Camera Non-linearized Full frame EDR
acquired on Sol 2 of Opportunity's mission to Meridiani
Planum at approximately 14:42:10 Mars local solar time,
camera commanded to use Filter 2 (20 nm).

 

So what happened to this object?

Here's a Black Helicopter theory: http://www.weirdload.com/nasa-shame.html

 

Well, that was fun!  Now let's see what the experts say:

"NASA Bunny Chase": http://marsrovers.jpl.nasa.gov/spotlight/opportunity/b19_20040304.html