Is the crested queen rare?

Excuse me, could you clarify something for me? I've come across a mention of the "crested queen" and I'm wondering if this is a particularly rare species or entity? Is it a type of animal, plant, or perhaps something else entirely? If it's rare, could you elaborate on why it's considered so and what sets it apart from other similar species or entities? Thank you in advance for any insight you can provide.