Ah, Halloween. The one night a year when everyone, not just cosplayers, can — nay, are expected to — dress up as any fantastical thing they want to be. Naturally, when given this freedom of self-expression, the choice of costume can reveal something about the wearer. (And to be clear, while the majority of such examples in fiction do happen on Halloween, this also applies for any other occasion when characters get to dress in their choice of costume.)