The chapter examines three monstrous archetypes presented in the selected novels by Peter Ackroyd - The House of Doctor Dee (1993), Dan Leno and the Limehouse Golem (1994) and The Casebook of Victor Frankenstein (2008) - as an indication of a peculiar alignment of the uncanny with the urban, a transgressive alliance resulting in the creation of a contemporary urban mythology based upon the idea of artificial life. The homunculus, the golem and Frankenstein’s monster are approached here as an instance of the urban abject as well as the doppelganger of the novels’ main characters. The core of my analysis is the complex relationship developed between the abject protagonist and the city, in which the latter both encompasses and rejects the former. As it happens, such ambivalence points to the maladies plaguing the polis in times past and present, as well as signals the potential threats to its future. It is, at the same time, a question about the very nature of the city, its semiotic underworld and the possibility of discovering the Transcendental Signifier in the serpentine streets of the postmodern urbanscape. It is therefore my contention that the subversive semiotic potential of Ackroyd’s characters and their monstrous incarnations paradoxically conditions the metaphysical foundations of the megalopolis.