This is a 9x13 double layer, chocolate cake with chocolate frosting.
For the lower "arm" I used a piece of cardboard covered in fondant to give it extra support. The two top "arms" are held together with chocolate to keep them sturdy. The joint in between the two arms was held together with a tooth pick and actually moved!
The "dirt" is just crumbled up cake and all other decorations are made from fondant.