Locals know the night before Halloween as Mischief Night. The term isn't used everywhere, and it sometimes confuses newcomers to the Philadelphia region. Mischief Night is an informal holiday on which children and teenagers engage in pranks and vandalism. In practice, this night is the “trick” part of “trick-or-treat” and not everyone agrees how it ended up that way. So we’re gonna take a look at the origins and endings of Mischief Night.