<p>For Descartes, nature must be interpreted through a limited number of simple laws used to describe the multiplicity of the real, focusing on the rule and normality rather than on the exception and monstrosity. Nevertheless, monstrosity has a vital function in Descartes' philosophy. By offering a new reading of the evil genius and the deceiver God in terms of absolute monstrosity, I intend to demonstrate the novel role played by the will in this philosophical ‘teratomachy’. Examining the peculiar status Admiration occupies in the economy of the passions, I also analyze a passage from the <em>Cogitationes circa generatione animalium</em>, the only text in which Descartes explicitly discusses physical monstrosities. I argue that...