It's called an interrobang. Never really took off but still available in unicode.

For future reference, ‽ is called an interrobang!

And to show off another fun character, for languages like Spanish that start a question with an inverted question mark, there's also ⸘, the inverted interrobang.

Though I find the name some people call it, gnaborretni (interrobang backwards), much sillier.

Interesting! If we were to follow Spanish to name the inverted interrobang it'd be opening (and closing) interrobangs, not gnaborretni, just as we don't have nóicagorretni nor nóicamalcxe :)

I assume you meant sgnaborretni?