When there's a movie premier that is popular in the pop culture, fans of a particular franchise want to dress up as their favorite characters.
When you walk into the event to pay for your ticket, if you have a Halloween costume, you can get in cheaper. In this adaption the "Costume 1" will refer to a normal Halloween costume, but it has to be a legitimate costume, you can't just ware a shirt that has a Batman sign on it, or say that you're an extra in a movie! That just won't fly for Costume 1!
This will be perfect for people to get clever with their costumes! If they want to save money for this event, they will need to get to know Shakespeare plays even more!