What is the term for a situation where the outcome is the opposite of what is expected?

Irony is a literary device in which there is a contrast between expectation and reality. This can manifest in several forms, such as situational irony (when the opposite of what is expected happens), verbal irony (when someone says the opposite of what they mean), and dramatic irony (when the audience knows something the characters do not). Irony is often used to create humor, add depth to characters, or highlight themes in a story. It can also serve as a tool for social commentary or to challenge the audience's assumptions.