Mirror, Mirror On The Wall
Imaginary friends are great. They’re the friends who can sleep over on school nights, and you don’t need to go through all the parental permission gymnastics involved in inviting them over because mom and dad won’t even know when they stop by. They’re quiet and don’t eat up all the food, so they’re parent-approved.
Having imaginary friends is no biggie, but when your kids start talking to the people living inside the mirrors, you know it’s time to take every reflective surface outside of your house and smash them to pieces before dumping them. The seven years of bad luck are better than whatever haunts the hidden dimension on the other side of the mirror befriending your kids.