Question mark
The rhetorical question mark or percontation point was invented by Henry Denham in the 1580s and was used at the end of a rhetorical question; however, its use died out in the 17th century. It was later revived in modern-day society by Matt DiRoberto. It was the reverse of an ordinary question mark, so that instead of the main opening pointing back into the sentence, it opened away from it. This character can be represented using the reversed question mark (⸮) found in Unicode as U+2E2E. The percontation point is analogous to the irony mark, but those are even more rarely seen.
Interrobang
"What the...?! Neves, Called Dead in Fall, Denies It" (headline from "San Francisco Examiner", May 9, 1936)
American Martin K. Speckter (1915 – February 14, 1988) conceptualized the interrobang in 1962. As the head of an advertising agency, Speckter believed that advertisements would look better if copywriters conveyed surprised rhetorical questions using a single mark. He proposed the concept of a single punctuation mark in an article in the magazine "TYPEtalks". Speckter solicited possible names for the new character from readers. Contenders included "exclamaquest", "QuizDing", "rhet", and "exclarotive", but he settled on "interrobang". He chose the name to reference the punctuation marks that inspired it: "interrogatio" is Latin for "rhetorical question" or "cross-examination"; "bang" is printers' slang for the exclamation mark. Graphic treatments for the new mark were also submitted in response to the article.