I’m looking for vampire metaphors in language.

Here’s my first find:

I’m starting to think there are two sorts of teaching-tired. There’s the, “OMG, these people are not doing their work and I am just terribly drained from having to carry this class!” tired.
…
I had a couple of vampire classes like this last year.

The metaphor is from Blogenspiel.

The picture is from Unexplained Mysteries.com.