It means October 31st is your birthday.
It means all your birthday parties will be costume parties.
It just means you get a lot of candy for your birthday.
It means everybody will be too busy to come to your birthday parties, so you are required to have it a few days prior to your actual birthday. It also means your parties will all be costume parties.
It means you were born on October 31.
It MEANS . . . You can go "Trick-or-Treating" on your birthday . . It carries no dark nefarious meaning. ;)
It means that you can have a Halloween themed birthday party.
a holiday you can go trick or treating or have a costume party.