Brilliant stuff! It's got that "tortoisy" feel about it. I was watching an episode of David Attenborough's excellent new series, "Life in Cold Blood" a couple of nights back, and it showed some fascinating footage of tortoises fighting each other. The males of this particular type had an elongated spike protruding from the carapace, just below the head, which they use as a sort of fulcrum lever, to wedge under their opponent's body and flip them on their backs. Amazing to watch.
Keep up the good work : )