Diplodocus wasn't the biggest of the long-necked sauropods, nor the hardiest. But it made up for that by evolving a tail so thin and flexible, paleontologists think it was an advanced weapon. Some even believe the tail could break the sound barrier — imagine having a whip attached to your butt! A predator approaching this guy might think it was just a regular sauropod... until a tail traveling at the speed of sound slapped it up, then it looked up to see the giant weirdo's creepy bucktoothed smile! It's fair to say ol' Dipsy sent quite a few attackers high-tailing. Artwork by Vladimir Nikolov.