Intelligent zombies are the rare instances where the zombie condition does not completely eradicate all evidence of thought. Some works of fiction depict zombies with personality and intelligence, the only difference being their hunger for flesh. They are extremely dangerous, as they can still use weapons such as guns or swords, and can devise plans to overcome human barricades, traps and the like. George A. Romero's Land of the Dead also depicts zombies slowly evolving/developing both a social hierarchy, and the ability to use tools and execute coordinated attacks.