FARGO — The Cass County Sheriff’s Office is warning parents of a new challenge or prank circulating on social media called “The Door Knock Challenge.” Jahner said he wants parents and guardians to talk with their children about the dangers of this challenge and the potential consequences, especially with North Dakota’s “Stand Your Ground” law. "A resident of that particular residence that the door is being kicked in might not realize that this is a prank, right?," he said. So they're going to protect their property more than likely, and especially if it's late at night, early in the morning. Jahner also said if homeowners see any suspicious activity or believe someone is trying to break into the home, call 911.