Ever wondered when Halloween shifted from spooky to sexy? Somewhere in the 1970s, explains Juliet Lapidos for Slate. New York’s Greenwich Village launched its annual Halloween parade in 1973, an event that quickly became popular among the local gay community, who largely attended in drag and other sexy outfits. The parade gained national fame and imitators sprung up. Retailers took note and began to push ever-bawdier costumes.
But it’s not just about ’70s drag queens, notes Lapidos—sexy dress has gotten a boost from “the more general skimpification of America,” too. Since Halloween isn't linked to a particular moment in history, it tends to reflect the wider culture, which "is more into revealed-cleavage than it once was, so it makes sense that Halloween has kept apace (in a parodic, pushing-the-envelope sort of way),” she writes.