This was a question that had always fascinated me: what are monsters for in stories? I mean, they’re there to menace the protagonists, of course, but what else? I found myself coming to the conclusion that monsters are very often presented as standing for something – some human trait taken too far, for instance. As an example, the Sontarans have humanity’s desire for war to the exclusion of all else. The Cybermen are an embodiment of the desire people often have to get rid of flawed bodies that get colds or break their legs, and replace them with something that can’t fail. Once in a while, you get monsters that are based on something else, like an animal’s characteristics – the Wirrn, say, or the Zarbi or the Macra. Perhaps the most interesting are Malcolm Hulke’s Silurians and Sea Devils, which in a sense are just humans that happen to look different from us.