We're at Halloween, originally the Celtic New Year Festive hijacked by the christians for a celebration of saints and souls and now, in Britain, an excuse to party midway to Christmas since Guy Fawkes/Fireworks night has becoming a bit pricey.
Whilst the UK tries to stick to the scary side of Halloween, many adopt the American idea that any outfit goes, which is fine, but sometimes for females the costume options can range from skimpy/sexy to downright strange: This is not the 'Since when was Halloween sexy?' debate. The costumes exist, people (mostly female) choose them, the market exists, end of story.
That said, the manufactuers do seem a little thin on novelty as in many cases the best they can offer is a female version of a male horror character - Miss Beetlejuice, Miss Scissorhands and Miss Jason spring to mind, and as for Miss Chucky, there was actually a Bride of Chucky character, but perhaps that would be too much effort.
It's not like there's a lack of fiendish females - Harley Quinn and the Suicide Squad offer great potential, but perhaps it's assumed if a girl's going to go gohulish, she's creative enough to do her own thing.
Stateside things are stranger: Fashion mag Cosmopolitan asked some non-models to try a few of this season's sexy costumes. All very good except that several were food-based - pizza, french fries, etc., others were based on undersea creatures and somehow a 'sexy Donald Trump is also featured. Obviously the definition of the term sexy is open ti interpretation.