Paraprosdokian
“The laugh laugh laugh cry formula,” she calls it. The audience thinks they are in the midst of a hilarious caper, and then they suddenly realize that this story is not what they expected.
Dan Kennedy • Storyworthy: Engage, Teach, Persuade, and Change Your Life through the Power of Storytelling
unexpected (another way to say “ironic”)
Blake Snyder • Save the Cat
Creating your own argot can start by twisting an existing word to convey an original idea.