"Trick or Treat" is a Halloween tradition where children dress in costumes and go door-to-door in their neighborhoods. They knock on doors and say "Trick or Treat," prompting homeowners to give them candy or other treats. If no treat is given, children may play a harmless trick, although this is rarely done today. This custom originated in the early 20th century and has roots in ancient practices like Samhain and All Hallows' Eve. Today, it is a fun way for communities to celebrate Halloween, fostering a sense of togetherness and excitement among children and families.