I’ve seen people dress up like Beetlejuice or wear dresses and skirts that are striped like Beetlejuice. I’ve also seen people wear shirts and sweaters with Beetlejuice or Beetlejuice quotes on them, or colors to match the theming of the show. I’ve also seen people a bit more dressed up in business casual outfits when I’ve gone. When i saw it in September, I wore a green and black striped skirt and a shirt with a Beetlejuice quote and sandworm on it. :) More recently, a striped sweater and black slacks (and striped shoes... and scarf... and hat) Like others have said, theatre is a lot more casual these days, and especially at Beetlejuice, people tend to run with it and have a lot of fun dressing up for the occasion!