Rock Monsters are enemies that appear in two Lego themes, "Rock Raiders" and "Power Miners". The former predates the latter by almost ten years. In "Rock Raiders", there was only one type of large, brown monster physically produced that appeared in two sets, though other types of monsters did appear in the video game adaptation. "Power Miners" introduced smaller monsters that came in several different colors. There were also a few larger variants, including the apparent leader of all of them, the "Crystal King".