B. Stoker

Mr B. Stoker was the head of the Royal Hope Hospital in London and supervisor to Martha Jones. When Royal Hope was transported to the Moon, he was killed by the Plasmavore "Florence Finnegan" by having his blood sucked out.

Behind the Scenes
B. Stoker is an obvious reference to Bram Stoker, the author of Dracula. Being that the Plasmavore was a blood sucking alien.