How many notes does a vampire have to whistle before he's referencing a popular video game franchise? That is the question at the heart of what may or may not be a shout out to Konami's long-running Castlevania franchise in the latest episode of HBO's True Blood, "9 Crimes". Some are saying that when vampire Eric rushes to help one of his human associates, he whistles four notes that sound a heck of a lot like the first four notes of the Castlevania "Vampire Killer" melody. Is the show actually referencing another famous piece of vampire fiction? Or is it just coincidence? Here's a brief video clip of the scene from the episode.