Carmilla is a Gothic novella by Joseph Sheridan Le Fanu. Carmilla is about a female vampire who prays upon young women. She's seen as a lesbian because of this. She has the ability to walk through closed doors and change form into a beastly cat. Camilla's real name is Countess Mircalla Karnstein, Carmilla being an anagram of Mircalla. The story of Carmilla predates Dracula by 26 years (Dracula was first released in 1897, whereas Carmilla was first published in 1871.)
Have a look at these gorgeous illustrations that decorated the original novella.