Self-Defeating Prophecy

The surest way to guarantee that you won`t win is to assume that you will.

—Brad Bird

The most common prophecy in fiction is a Self-Fulfilling Prophecy—people's reactions to the prophecy, whether to try to prevent it or to aid the Chosen One, end up causing it to happen. But the inverse is also quite common: a prophecy that would be inevitable, were it not for the existence of the prophecy.

Generally, a single person knows that something terrible will happen in the next 24 hours...unless that person can use her special knowledge to prevent it. More rarely, a person will accidentally thwart a good prophecy by trying to force it, or the prophecy will simply fail For Want of a Nail; the prophecy itself is the nail.

In Real Life, predicting that something terrible will happen often allows you to prevent it. Intelligence is an awesome power.

Compare Either/Or Prophecy, where the potential for thwarting is spelled out in the prophecy itself, and Set Right What Once Went Wrong, where the plot is nearly identical but the cause is Time Travel. Overlaps with Screw Destiny, where the prophecy is claimed to be inevitable but people hope it's self-defeating instead.

Examples of Self-Defeating Prophecy include:

Cross-Media

The visions in Minority Report. In the original short story, this is taken to an extreme: one precog sees the future as it would have been if there were no visions. The second sees the future as it would have been if only the first vision existed. The third sees the future as it would have been if only the first two visions existed.
The visions in The Dead Zone.

Literature

In the Temps Shared Universe, this is called the "Oedipus paradox", which researcher Simon Sweetland notes is completely wrong, because that was a Self-Fulfilling Prophecy.
In the Book of Jonah the prophet announces that the city of Nineveh will be destroyed. People of the city repent, so the destruction doesn't takes place (at least not immediately).

Live Action TV

The premise of many early Angel episodes.
The premise of most Early Edition episodes. The hero gets tomorrow's newspaper, which generally seems to predict the day as it would have gone had the newspaper not existed.
A regular occurrence on Eli Stone: Eli would get visions and try to prevent them from happening - like, his vision said a building was going to get bombed with his boss in it, so he tried to get his boss to leave the building before that happened. Sometimes it worked out in his favor, sometimes not.
Eureka does this with Mental Time Travel rather than prophecies. The season 1 finale has Carter travel back in time from a point where he's married to Allison. As a result, in the season 2 opener, he acts overly familiar with her, she's mildly put off, and they don't go on their first date as he remembers it; in the end that first date doesn't happen for almost three more years.
Whether or not this is possible is a major question for the characters of FlashForward.
In Charmed, Phoebe's premonitions allow the sisters to prevent almost all of the tragedies she sees. It tends to be a real Tear Jerker on those rare occasions when they can't.
The Fades has two:
- Paul twice has a prophetic dream in which he sees his loved ones dead; he's able to avert this because, when the time comes, he recognises the dream's circumstances and is able to check on them before the killer can get to them.
- Part of the apocalyptic prophecy Paul and Sarah have been seeing involves Paul being stabbed to death at the end of a fight with John, the Big Bad. However, when the fight with John actually comes, Sarah takes the stab wound instead to allow Paul enough time to save the day, having only known to do this because of her visions.

Video Games

The Dark Prognosticus in Super Paper Mario is a book that details a series of events that would come to destroy all universes. The Ancients, in response, created a counter-prophecy in the Light Prognosticus.
Xenoblade revolves around this-not only do Shulk's Monando-born visions allow him to change the course of the study, it's actually a system in game: An enemy charging a powerful attack will provoke the Monando to show you ahead of time what happens, so you can prepare for it or even stop it from happening in the first place.

Webcomics

Dominic Deegan's second sight shows the unaltered future: What the future will be if he doesn't do something specially to change it. In fact, later on when he gets a vision of doom for his friends, Dominic takes it as a good thing—because he had the vision, that means he can change what's going to happen.
- One early example example is in the first story arc. He is looking for a cure to a curse and his vision directs him to the home of the person who cursed him, which has a potion to remove it. When he gets there that person's daughter undoes the curse herself. He wonders why he didn't see that coming, and realizes a moment later that his vision was of the unaltered future in which she had already hung herself.
In Homestuck, Terezi has the power to see the consequences of certain actions. For example, in a doomed timeline she lets Vriska go, which results in the deaths of every troll excluding Vriska and Aradia, and Vriska might not have lived much longer. She foresees these consequences in the alpha timeline. However, since she knows that in the alpha timeline, she and Karkat have to live for at least another two hours, she kills Vriska before that can happen.
Offshore Comic #297, on the tricky part of social science. Once someone publishes a model based on pre-existing data, a lot of people will see and try to game it. Thus it will be broken by feedback before it's much use to anyone, and probably before its forecasts can be reliably confirmed (assuming it was any good in the first place).