Oh, Crap!
aka: Real Life

"It's that moment of dawning comprehension I live for."
Hobbes, Calvin and Hobbes

The moment at which a character realizes that something really, REALLY bad is about to happen. Either that, or it already has, and they are in big trouble because of it. They may not always say anything in particular when they do, but even if they don't, the look on their face clearly conveys to the audience their realization. This moment often features stronger language, and is when they truly realize that the solid organic waste is about to collide with the Rotational Air Circulation Device.note  Sometimes the first few notes of Chopin's Funeral march is used as background music to highlight how grim the situation is.

They may feel that This Is Gonna Suck, and often exclaim, "You Have Got to Be Kidding Me!" or perhaps "I Want My Mommy!" or sometimes even "This Cannot Be!" Other characters might emit a Loud Gulp instead. Some might even freeze in fear completely.

The effectiveness of this moment can be affected by the difference between their usual competence and confidence levels and how completely they are boned. Characters with low self-esteem or who are constantly crying out in terror are difficult (but not impossible) to make this trope work with. But that arrogant, so far unbeatable supervillain suddenly realizing they're about to have his ass royally kicked? Now we're talking!

Can occur if one protagonist has been luring the other one into a trap, or if they just have some shiny new skill. Or they may simply be a lower-level villain who's just had the very bad luck to be confronted with a hero impossibly out of his league. On occasion, they will be discussing the situation when they realize the full import of it. Related to This Cannot Be!, and the polar opposite of Obi-Wan Moment, when despite the bad situation someone still manages to look composed. May result in a Heroic B.S.O.D. for a heroic character, or even a Villainous Breakdown for a villainous character. Nine times out of ten, this will immediately follow "What does this button do?". The remaining tenth follow some other temptation of fate. Also a very common reaction when a villain, normally a Chess Master, Villain with Good Publicity, or Manipulative Bastard, realizes they've just been the victim of an Engineered Public Confession. Some characters react with less despair and more apathy; others look to their equipment for a solution. And for some, it is the crowning moment of despair.

When this trope becomes literal, that's Bring My Brown Pants—as Bill Cosby once said, "first you say it, then you do it!"

May also be a Precision F-Strike for the person in question.

When most of the cast available in the scene does this expression, it's a Mass "Oh, Crap!" moment. If someone tries to explain the situation to someone else, and realizes half-way through their own explanation they're in real trouble, it's Explain, Explain... Oh, Crap!. If the person making the realization doesn't try to explain and says nothing but "Run," it's time to Run or Die. If you realize you're in trouble after your explanation, it's a Delayed "Oh, Crap!". When you try to save some face by putting on a happy face, you make an "Oh, Crap!" Smile. When you pretend to realize you are in trouble only to mess with your opponent, it's an "Oh, Crap!" Fakeout. When your primary reaction is resigned acceptance of the situation, it's This Is Gonna Suck. When a character soils him or herself upon this realization,note  it's Bring My Brown Pants.

See also Wide Eyes and Shrunken Irises. Say Your Prayers may be involved as part of this reaction.

Contrast "Hell, Yes!" Moment, the exact inverse.

Warning: High risk of spoilers.

Examples go in subpages: