Looking back through my earliest notebooks, however, I found that on my very earliest list of staff, there was a subjectless vampire teacher I had forgotten, called ‘Trocar’. A Trocar is sharply pointed shaft inserted into arteries or cavities to extract bodily fluids, so I think it a rather good name for a vampire. Evidently I did not think much of him as a character, though, because he disappears fairly early on in my notes.
For a long time there was a persistent fan rumour that Snape might be a vampire. While it is true that he has an unhealthy pallor, and is sometimes described as looking like a large bat in his long black cloak, he never actually turns into a bat, we meet him outside the castle by daylight, and no corpses with puncture marks in their necks ever turn up at Hogwarts. In short, Snape is not a revamped Trocar.