It is now common knowledge that vampires can turn into bats but prior to Bram Stoker’s seminal 1897 novel “Dracula” the connection was not so obvious. “Dracula” . . . solidified popular knowledge regarding vampire lore.
So now the question is, what has contributed to the success of this iconic vampire series? I think at this point the producers are playing it smart, and cashing out their chips while they are on a winning streak.