Peter and Mary Jane (Watson!) Parker. From "Amazing Spider-Man" #311 (pencils by Todd McFarlane). No, it's not a Halloween issue. They just went out dancing like that. It was a normal thing for them at the time. Why, here's how they dressed just a couple issues earlier:
The Parkers were a fashion challenged family for quite a long time. I'm no expert, but just look at this. Who knows, I might milk this topic some more in future posts.
Happy Halloween! (and see ya again in a couple of days!)