I'm working on this new story in which many people have developed "special qualities" or gifts - call it extreme DNA mutations, if you will. There's this character who has several rows of teeth (maybe they also grow back easily?), and because of it, he's really interested in sharks! So I wanted to give him a bit more than that, and therefore, I was wondering how crazy these two traits would be for a human being to have:
Being able to dislocate their lower jaw
Having a cartilage skeleton
Seriously, I have no idea what consequences this would result in. Is cartilage resilient enough to carry a human body? Is its elasticity impairing in some way? Or would it help him resist punches and so? Would he have any trouble carrying heavy things or am I going bonkers?