This is an interrobang. It should have become a punctuation mark, but it never really caught on. Maybe it will in the future, but probably not. The keyboard is pretty well standardized by this point, and people seem happy enough to say, “He hooked up with Sheila?!?!??!”
I think about the interrobang a lot when I am thinking about the habit we have, as a species, of assuming that the world in which we live was entirely inevitable—that we as contemporary humans are just along for the ride. But the truth is we all make up the world together as we go. We choose ?! over the interrobang. I know it feels like someone else has made this decision for us. But the truth is that together, we are making the decision right now.
I will now start using the interrobang in inclass written essays, just to tell my English teacher about it when she asks.