Greek fire

Greek Fire was a deadly weapon invented by the Byzantines in the Middle Ages used to destroy ships in the water. They were generally put in jars which were placed into bomb like packets. Oil was mixed in with the mixture, and it was ignited when catapulted. When launched, it looked like a continuous fire shooting from the ship; it was extrememely deadly. At one point,, Blackbeard aqcuired the recipe, and used it while on the Queen Anne's Revenge during the Quest for the Fountain of Youth

Appearances
Pirates of the Caribbean: On Stranger Tides