Okay, this one isn't technically a dinosaur but come on. Far from the sleek, scary killing machines that we imagine of most sharks, Stethacanthus was the wheezy one who once ripped his mole off in P.E. This guy definitely had to say the words "quit teasing, it's just a birthmark" on the regs. Experts aren't exactly sure why Mother Nature decided that an anvil-shaped dorsal fin was a good look. Some reckon that it was used for mating (if she could stop laughing for long enough), some reckon it was for suctioning to the bottom of larger animals (oh yes, did I mention that Stethacanthus is only 70cms long? Not exactly Jaws). But I suspect that it was manly used by the class bullies to see how many things they could stack on it before Steth noticed and told the teacher.
