Dramatic irony. Basically, it's when the audience/reader knows something that the characters in the story don't. Usually when dramatic irony is used (like in all suspense novels), tension is created, but when dramatic irony is used in the context of humor, it can build anticipation.
For example: a character can be used to create dramatic irony. In a scene where a particular character (usually someone mischievous or characteristically "unlucky") steps into the room the main character/s are in, the reader would be thinking
"Oh boy, here we go" but the characters have no idea something strange is bound to happen. And as the scene goes on and the other characters neglect to understand the peril they are in (be it danger or just an unfortunate and comical inconvenience), the anticipation for the little catastrophe gets stronger and larger until it finally happens.
Another way to use dramatic irony for humor is through a certain object. Something that will cause the character who naively picks it up a world of trouble. I think a perfect example of this is the classic scene of the movie
Home Alone. You know, where young Kevin is in the bathroom, trying out his father's aftershave. All the adults watching probably knew what would happen, which made Kevin's abrupt realization that the stuff
stings even funnier (and pitiable).
Scenes where a character is mistaken or being tricked can also be hilarious. There's a great example of this in the movie
Esther (the 1999 version). Basically, there's a scene where the king of Persia is trying to come up with a way to honor one of the main characters. As he does so, the villain Haman (who hates the aforementioned main character) shows up, and the king asks him for assistance in coming up with a reward. Thinking that the honor is for himself, Haman starts listing a bunch of lavish rewards. The king accepts the ideas readily, and in the very next scene . . . bam! Not only is that following scene hilarious, but the build-up of Haman's eager dialogue makes the viewer chuckle the whole time. There's also an example of this kind of thing in Shakespeare's
Twelfth Night, involving a contagonist, a cruel prank, and a forged letter. One can't help but feel sorry for the deceived Malvolio as he gets excited about a trap, but at the same time it's hard not to snicker just a little bit as he arrogantly struts into the setup.
"The little bubble of obliviousness." That's what I like to call this next example of humorous dramatic irony. It's most effective in something visual like a movie or a TV show, but I've seen it in at least one book, and it was so hilarious that I burst out laughing. The bubble of obliviousness is basically a short scene (usually near the climax) where the main characters are running around in a panic trying to solve (or just survive) a problem, and the situation is hectic and tense, but right smack in the middle of it (either walking into the scene or lingering in a small corner of it) there's another character being completely unaware of the panic. The character is usually doing something casual and relaxed like reading or eating a banana, and maybe interrupting the others to ask what's happening, and the response that character gets and the contrast between them and the others is hugely laughable!
Do any other examples of dramatic irony being used humorously come to mind? Please feel free to share in the comments section! :)