"I'll explain Halloween too you to if you want." Leda smiled. "But basically, trick or treating, you dress up in a costume. Any costume. Some people go as something scary, some go as their favorite fictional character. Didi's dressing up as a girl from 1920's Earth. But anyway, then you go around town, and go up to people's houses or business, and when they answer the door, you yell 'Trick or Treat'. And they give you candy."