Mircalla Karnstein (Ingrid Pitt), a female vampire, preys on her sleeping victims in the form of a cat.
What looks like a panther may in fact just be a distorted negative of the late actress' very feline face.
After Laura (Pippa Steele) has a nightmare about a huge cat choking her, Mme. Perrodot (Kate O'Mara) blames their household cat Gustav.
Even though the governess then goes as far as placing Gustav in front of a lamp to show how his shadow would appear giant sized on the wall, he's clearly not a vampire. You can't rearrange the letters in his name into another stupid name for one thing.
Later, Emma Morton (Madeline Smith) also dreams of a cat as big as a wolf. "It was grey and had enormous eyes!" she yells.
Okay, so maybe it was a very well fed Gustav after all.