Invented by Byzantines, Greek fire was a fearsome weapon. It had the ability to keep burning while on water. As such, it was often used in naval battles. The creation of it was a closely guarded secret and has now been lost. It was very similar to modern napalm, though it was weaker. Byzantine ships attached it to their fronts as a medival sort of flamethrower. After several accidents of the fire burning its own ship, it was no longer used.