A French legend that sprang up around the name of St. Romanus ("Romain") (AD 631–641), the former chancellor of the Merovigian king Clotaire II who was made Bishop of Rouen, relates how he delivered the country around Rouen from a monster called Gargouille. La Gargouille is said to have been the typical dragon with batlike wings, a long neck, and the ability to breathe fire from its mouth. There are multiple versions of the story, either that St. Romanus subdued the creature with a crucifix, or he captured the creature with the help of the only volunteer, a condemned man. In each, the monster is led back to Rouen and burned, but its head and neck would not burn due to being tempered by its own fire breath. The head was then mounted on the walls of the newly built church to scare off evil spirits, and used for protection.
But to be fair, a gargoyle is in Architecture a carved or formed grotesque figure with a spout designed to convey water from a roof and away from the side of a building, thereby preventing rainwater from running down masonry walls and eroding the mortar between.
Many medieval cathedrals included gargoyles. Architects often used multiple gargoyles on buildings to divide the flow of rainwater off the roof to minimize the potential damage from a rainstorm. A trough is cut in the back of the gargoyle and rainwater typically exits through the open mouth. Gargoyles are usually an elongated fantastic animal because the length of the gargoyle determines how far water is thrown from the wall.