The Doctor and the Devil

One of my favorite Doctor Who tropes is the use of alien creatures to explain legends and myths (as well as integrate these creatures – in a very Doctor Who-esque way – into the show).  We’ve seen a Haemovariform crash-land on Earth and be mistaken for a werewolf in Scotland in 1879 (S2,E2).  There was a band of Saturnyns creating vampire-like “brides” for their remaining male population in 1580 Venice (S5,E6).  The reason beings on most planets are instinctively afraid of the dark is explained with the presence of the flesh-eating Vashta Nerada, who we see as the dust in sunbeams (S4,E8).  The occasional movement we see flicker, out of the corner of our eye, when we look in mirrors is the “daughter” of “the Family of Blood,” forever trapped in all mirrors by the Doctor (S3,E9).  The list goes on.  But the one most fascinating to me is when the Doctor and Rose encounter “the Beast.”