Pondering Halloween in SL

Okay, I'm confused. If I put on a mermaid tail, is that my avie or is that my Halloween costume?

In a world where people can be anything they want, what do you wear to a costume party?

Bibi Book wears a witch's hat all year long. If she takes off her hat, would the absence of her hat be her Halloween costume? Would October 31st then be a "Nah-loween" day for her?

And, with your name tag floating above your head, what's the point of a masquerade ball? I mean, 90% of the men wear the same couple of skins, so that's pretty much like wearing a mask.

Who knew that choosing a Halloween costume in virtual reality would be so much harder than choosing one in real life? How do you put together a costume that won't be mistaken as an avie?

/me wonders if she needs a hover text that says, "This is my Halloween costume."