I believe this is the "Rover and Lander" unit during EDL (Entry, Descent, Landing). It is a tetrs that has airbags around it and evenually deflates when it is done bouncing. Then opens up like a flower, no matter if it is on its base or flaps. This system was used on both Sojourner, Spirit, and Opportunity.
http://www.jpl.nasa.gov/missions/mer/