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.
Wondermark
In 2014, the word "sea lioning" (also rendered "sea-lioning" or "sealioning") was coined based on a "Wondermark" strip, referring to a type of Internet trolling which consists of bad-faith requests for evidence, or repeated questions, in an attempt to derail a discussion or to wear down the patience of one's opponent. In the comic strip, a character expresses a dislike of sea lions, and a sea lion immediately appears, following the character around to repeatedly ask why that is.