I don't know about H. P. Lovecraft (I mean, I do know about HPL but I don't remember any vampire squids or octopi, specifically) but there was an old E. C. comic about a vampiric octopus.  I think it was in an issue of The Vault of Horror.

Yeah, my impression is that once she was no longer Nucky's "Little Tiger Cub" they weren't sure how to keep her in the story.