My mother was driving home and she got a message from my sister asking when she was gonna arrive. To that, my mom replied "half an hour" "more or less". Then she gets a reply of my sister saying "Jenny has exclaimed AH to your message more or less" (Jenny is the way my mom has my sister added on her phone), and after she read it, the message disappeared. Mom asked my sister if she had exclaimed "ah". My sister denied it, and was confused, so she sent a screenshot showing that she hadn't sent anything. Mom thought she was crazy but my father was next to her and even though he didn't see the message before it had disappeared, he could hear the phone ring. Both of them have Iphone and I was wondering if that is product of some weird iphone feature. She now told me it wasn't a message, but more like a notification. This makes me believe it was indeed a feature of iMessaging or something. I have tried to find it though, and couldn't.