A post from guest blogger Nick Ballard:
The interrobang (/ɪn’tɛrəbæŋ/) (‽) is a rarely used, nonstandard English-language punctuation mark intended to combine the functions of the question mark (also called the interrogative point) and the exclamation mark (known in printers’ jargon as the bang). The typographical character is a superimposition of those two marks. The same effect is also frequently achieved by placing the exclamation point before or after the question mark; e.g., “How could you do such a thing!?” or “How could you do such a thing?!”
A sentence ending with an interrobang either (1) asks a question in an excited manner, (2) expresses excitement or disbelief in the form of a question, or (3) asks a rhetorical question.
How much did you spend on those shoes‽
You’re going out with her‽
She did what‽