A Gargoyle is a living monster that is created from stone. They come in many varieties: some are full bodied, often with wings; others are simply disembodied visages that simply watch (ex. having only half a body). Gargoyles are not the same as other stone beings, such as the Golem, as Gargoyles are always in the form of in-human, possibly demonic, creatures. They stand guard in gothic-style structures, such as Cathedrals and European castles.
It has also been said that Gargoyles only come alive to fend off evil, which would explain them being found on churches commonly. So there is a possibility that Gargoyles just possess frightening and malevolent appearances to fend off intruders. It is also said in some small legends that they are a type of lesser gaurdian angel that is at times often considered to be an abomination due to the fact that they are half-angel and half-demon. Therefore, it is unknown whether a Gargoyle is benevolent or malevolent.
The name "Gargoyle" comes from the Gargouille, a Dragon that spouted water from its mouth, causing floods. Gargoyles, the stone decorations, were originally representations of this monster.