You have been texting with a friend. At some point. Your friend is no longer available, but does not want you to know that.
So your friend switches into bot mode. You are now texting with an entity that says all the things your friend would say, but is actually an AI mirror of that person.
This is not quite possible now. We can tell pretty quickly when we are talking with a fake intelligence. But at some point this scenario will start to enter the realm of everyday reality.
Of course this won’t happen all at once. Rather, as the years go on, the length of time it will take to detect such a fraud will gradually lengthen. But then, at some point, a line will be crossed, just as a line was eventually crossed with chess playing computers.
And from then on we will look back with nostalgia upon an earlier and more innocent time, when you knew for sure that the person you were talking to was actually a person.