This essay develops my earlier work on the influence of Dr John Polidori’s ‘The Vampyre’ on Mary Shelley’s novel Frankenstein (1818) – both were conceived at the Villa Diodati during the summer of 1816, and Frankenstein has deep affinities with the vampirelore that was evidently aired during conversations between Lord, Byron, Percy Shelley, Mary Godwin (later Shelley), Claire Clairmont, and Polidori (see The Vampire: A New History (Yale University Press, 2018), 119-25; see also D. L. Macdonald, Poor Polidori: A Critical Biography of the Author of The Vampyre (Toronto, Buffalo, and London: University of Toronto Press, 1991), 85-87). But the influence was also reciprocal, and Frankenstein echoes through Polidori’s tale in unexpected ways. The character Aubrey has often been seen as a self-portrait of Polidori while it is generally accepted that the vampire Lord Ruthven is an audacious attack on Byron, who employed Polidori as his personal physician. However, in this essay I will present a radical and unsettling close-reading of the character of Aubrey, informed by Mary Shelley’s presentation of Victor Frankenstein, arguing that the relationship between Aubrey and Ruthven is far more complex and uncanny than has hitherto been recognized.