Gargoyles are stone figures placed on the walls of cathedrals and castles, often with fearsome faces designed to strike fear in all who see them. From a practical standpoint, they also serve to prevent water from running down the walls and eroding away the stone.
Though gargoyles are mostly associated with medieval architecture, waterspouts shaped into the form of grotesque creatues can be found in much older cultures, in locations including Ancient Egypt, Ancient Greece and 1st Century B.C. Afghanistan.
The word "gargoyle" comes from the French "gargouille", which means throat or gullet. The words "gurgle" and "gargle" are rooted in the same word. The word became associated with the sculptures through the legend of a dragon called "La Gargouille" or "Goji". This dragon is said to have terrorized and flooded a village until a priest named Romanus arrived and killed the beast. Its body was burned but its head would not catch fire, so it was affixed to the front of the church, becoming the first "gargoyle".
Gargoyles are designed to be fearsome and scary in an effort to protect the building from evil spirits. While most frightful sculptures atop buildings are called gargoyles, any such sculpture without the water spout functionality is more correctly referred to as a chimera, grotesque or boss.