The self-portrait shows Mount Sharp in the distance, which is the final destination of the Rover. These high-definition images are released to the public in websites such as Unmanned Space Flight and enhanced in order to display an earth like colouring. Portraits like the one shown on the left, are used by NASA engineers to track dust accumulation on the vehicle and tire wear.
It should be noted the picture does not show the arm that connect the camera to the rover; this is because the image is produced using a collection of images stitched together with technology much like the ones that we use on our smartphones to make panoramic photos.
It is not yet known (at least to the general public) what the protrusion is made of, but that hasn't stopped people from flocking to forums such as Above Top Secret to speculate about the image. For now all we can do it wait for official releases from reliable entities.
Further information on these "out of place" objects can be found with a simple Google search or a visit to pages such as OOPARTS which provide some introduction and discussion of these artifacts.
By: Edmundo Rodrigues