In the ancient world and right up through the Middle Ages, people told tales of monstrous giant reptiles called dragons, which sometimes sported bat wings and barbed tails, and wreaked carnage by breathing fire [source: Encyclopaedia Britannica]. But that macabre fantasy creature turns out to have a real-life cousin.
In 1912, naturalists discovered the Komodo dragon (Varanus komodoensis), a lizard from Indonesia that grows up to 11 feet (3.5 meters) in length. These reptiles are plenty scary in their own right. They're carnivorous hunters, and on occasion they've even dined upon humans. While they lack fiery breath, they exhale something nearly as deadly — a virulent bacteria, which infects wounds caused by the dragon's teeth and causes them to rot and fester [source: Slifkin and Slifkin].