What is a blumkin?

There's no known creature or object called a "blumkin" in established biology, mythology, fiction (with significant presence), or common usage. It's possible:

• It's a misspelling: Could you be thinking of a different name? Perhaps a similar-sounding creature or object?
• It's a very obscure reference: It might be from a niche piece of fiction, a private joke, or a very localized term.
• It's a newly invented word: Someone might have recently created the term.

If you can provide more context (where you encountered the word, what it was described as, etc.), I might be able to offer a more helpful response.