Anagnorisis

Anagnorisis is a moment in a play or other work when a character makes a critical discovery that sends the story inevitably to its ultimate conclusion. Anagnorisis originally meant "recognition" in its Greek context, not only of a person but also of what that person stood for. Anagnorisis was the hero's sudden awareness of a real situation, the realization of things as they stood, and finally, the hero's insight into a relationship with an often antagonistic character in Aristotelian tragedy.

A humorous definition is included in the mock-Epic Poem Chronicles of Halden, II: The Banner, by Robin Gordon, in its first part, "Sid":

The poet's comments form the choruses,
but now it's time for anagnorisis.
When Oedipus sees the bird he's bedded
is his own father's lawful wedded
wife, in fact she is his mother,
or Iphigenia finds her brother,
Discovery or Recognition
brings the plot to its fruition.

Anagnorisis is often part of the "revelation" in Go Mad from the Revelation. It is also often a key part of a Twist Ending.

Sub-Trope of The Reveal. Originally defined by Aristotle in his Poetics, making it Older Than Feudalism.

Examples of Anagnorisis include:

Film

The famous Twist Ending of The Sixth Sense.
Similarly, the revelations at the end of Unbreakable.
Possibly the best-known example in pop culture would be the moment in The Empire Strikes Back where Darth Vader reveals that he is Luke's father.

Literature

"The Three Apples", a Murder Mystery from The Arabian Nights, uses an incident of Anagnorisis as the pivot for its ending, which is the solution of its central crime.

Theatre

The Zeroth Law of Trope Examples applies here. That most famous soliloquy from Hamlet, "To be or not to be...", defines how Hamlet sees himself in relation to the world and people around him.
- Similarly, the scene at the end of The Winter's Tale in which it is revealed that Perdita is a king's daughter rather than a shepherdess, and thus is a suitable mate for her lover, a prince.
- Likewise, The Comedy of Errors ends once the twins have discovered and understood each other's existence.
The climax of The Importance of Being Earnest, where the truth of Algernon's parentage is discovered.
As noted in the passage from The Banner, the moment in Oedipus Rex when he discovers he has killed his father and married his mother.
In Little Shop of Horrors, anagnorisis comes when Seymour realizes Audrey II had planned the entire course of events leading to him becoming Audrey's accomplice in conquering the world right from the start.