Our family group chat is called Fam ❤️. Five people. Me, Mom, Dad, my sister Zoe, my little brother Sam. Tonight my phone buzzed and the header said 6 members. The new one had no name. No profile photo. Just a gray circle. Mom: "who is this??" Three dots. Typing. Then it sent one photo. Our living room. The couch. Dad's mug on the coffee table, still steaming. Taken from inside the house.

Dad: "Nobody move. I'm going downstairs." Me: "dad don't" Zoe: "DAD PLEASE" We all watched the chat instead of moving. The gray circle started typing. It typed for a long time. Way too long for what came out. One line: "Tell him to check the closet first."

Dad went anyway. We heard the stairs creak through the floor, one by one. Dad: "closet's empty. living room's empty." Mom: "then come back UP" Dad: "hang on. the back door is open." The gray circle posted a new photo. Dad. From behind. Standing at the back door with his phone in his hand. Me: "DAD BEHIND YOU" The three dots started again.

Dad spun around. We heard him yell "WHO'S THERE" right through the floor. Dad: "nothing. there's nothing here." The gray circle: "He's looking too low." Dad: "what does that mean" The gray circle: "Look up." The whole house went quiet. Then Dad's three dots appeared. And stopped. And appeared again.

Dad didn't answer. Mom grabbed the bat from her closet and ran down, and I ran after her. Dad was standing in the kitchen, staring at his phone, not blinking. "It messaged just me," he said, and turned the screen around. "Thank you for opening the door. I've been knocking for thirty years." Behind him, the back door stood wide open. Dad swears he locked it. He always locks it. We moved out within the month. The new family's kid goes to my school. Last week he stopped me in the hall and asked, "Hey. Did your family chat ever say six?"